Lighting device

Abstract

The present invention provides a lighting device that can secure the necessary luminous flux for illumination within a limited substrate area while setting a steep cut-off line above the direction of maximum brightness of the illumination light. [Solution] The lighting device 1 comprises a plurality of light-emitting elements 21a and a plurality of lenses 261. The plurality of lenses 261 include a first lens 263 and a second lens 264. The first lens 263 corresponds to the first light-emitting element 21c and emits light upward from the first direction of maximum brightness. The second lens 264 corresponds to the second light-emitting element 21d and emits light downward from the first direction of maximum brightness. The first ratio is greater than the second ratio. The first ratio is the ratio of the height L10 of the first lens 263 to the first light-emitting area H10 of the first light-emitting element 21c. The second ratio is the ratio of the height L11 of the second lens 264 to the second light-emitting area H11 of the second light-emitting element 21d. The first light-emitting area H10 of the first light-emitting element 21c is smaller than the second light-emitting area H11 of the second light-emitting element 21d.

Description

Technical Field

[0001] The present disclosure relates to a lighting device, and more particularly to a lighting device used as floodlighting.

Background Art

[0002] The light source unit according to Patent Document 1 includes a plurality of light sources provided on the main surface of a light source substrate and a plurality of lens bodies corresponding to the plurality of light sources. The plurality of lens bodies receive light from the corresponding light sources and emit the incident light.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0007] An illumination device according to one aspect of the present disclosure comprises a plurality of light-emitting elements and a plurality of lenses. The plurality of light-emitting elements are arranged on the main surface of a substrate. The plurality of lenses correspond to the plurality of light-emitting elements. Each of the plurality of lenses has an incident surface, an exit surface, and a reflecting surface. The incident surface is concave. The incident surface faces the corresponding light-emitting element. The reflecting surface connects the end of the incident surface and the end of the exit surface. The plurality of light-emitting elements include a first light-emitting element and a second light-emitting element. The first light-emitting element has a first optical axis. The second light-emitting element has a second optical axis. The plurality of lenses include a first lens and a second lens. The first lens corresponds to the first light-emitting element and emits light upward from a first maximum brightness direction, which is the light distribution direction in which the luminance of the combined light of the emitted light from each of the plurality of lenses is maximized. The second lens corresponds to the second light-emitting element and emits light downward from the first maximum brightness direction. The first ratio is greater than the second ratio. The first ratio is the ratio of the area of ​​the first emission surface of the first lens to the first light-emitting area of ​​the first light-emitting element. The second ratio is the ratio of the area of ​​the second emission surface of the second lens to the second light-emitting area of ​​the second light-emitting element. The first light-emitting area of ​​the first light-emitting element is smaller than the second light-emitting area of ​​the second light-emitting element. [Effects of the Invention]

[0008] According to one aspect of the present disclosure, a lighting device can be used to secure the necessary luminous flux for illumination light with a limited substrate area, while setting a steep cut-off line in the direction of maximum brightness of the illumination light. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view showing a lighting device according to an embodiment. [Figure 2] Figure 2 is a perspective view showing the lighting unit of the lighting device described above. [Figure 3] Figure 3 is an exploded perspective view showing the lighting unit of the same lighting device. [Figure 4] Figure 4 is an enlarged cross-sectional view of the main part of the lighting device shown above. [Figure 5] Figure 5 is an enlarged view of the main part of the lighting device shown above. [Figure 6] Figure 6 is an explanatory diagram illustrating how the emitted light from the first light-emitting element of the illumination device described above propagates after passing through the first lens. [Figure 7] Figure 7 is an explanatory diagram illustrating how the emitted light from the second light-emitting element of the same lighting device propagates after passing through the second lens. [Figure 8] Figure 8 is an explanatory diagram illustrating the light distribution characteristics of the lighting device described above. [Figure 9] Figure 9 is an explanatory diagram illustrating the case where the light-emitting area of ​​the light-emitting element corresponding to the lens is changed. [Figure 10] Figure 10 is an explanatory diagram illustrating the change in the light distribution characteristics of the lens when the light-emitting area of ​​the light-emitting element is changed. [Figure 11] Figure 11 is an explanatory diagram illustrating the relationship between the light distribution characteristics of the lighting device described above, the light distribution characteristics of the first lens, and the light distribution characteristics of the second lens. [Figure 12] Figure 12 is a cross-sectional view of the same lighting device. [Figure 13] Figure 13 is an explanatory diagram illustrating the arrangement of multiple lenses in the same lighting device. [Figure 14] Figure 14 is a cross-sectional view of the lighting device according to modified example 2. [Figure 15] Figure 15 is an explanatory diagram illustrating the arrangement of multiple lenses in the same lighting device. [Figure 16] Figure 16 is an explanatory diagram illustrating the relationship between the light distribution characteristics of the lighting device according to Modification 2, the light distribution characteristics of the first lens, the light distribution characteristics of the second lens, and the light distribution characteristics of the third lens. [Figure 17] Figure 17 is an explanatory diagram illustrating the change in the optical distribution characteristics of a lens when the ratio of the area of ​​the lens emission surface to the light-emitting area of ​​the light-emitting element is changed. [Figure 18] Figure 18 is a graph showing the relationship between the brightness of the light emitted from the lens at a 15-degree angle above it and the ratio of the area of ​​the lens's emission surface to the light-emitting area of ​​the light-emitting element. [Modes for carrying out the invention]

[0010] Hereinafter, an illumination device according to an embodiment of the present disclosure will be described in detail with reference to the drawings. However, each of the drawings described in the following embodiments is a schematic diagram, and the respective ratios of the sizes and thicknesses of each component do not necessarily reflect the actual dimensional ratios. 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.

[0011] (Embodiment 1) (1) Overview As shown in FIG. 12, the lighting device 1 according to Embodiment 1 includes a plurality of light-emitting elements 21a and a plurality of lenses 261. The plurality of light-emitting elements 21a are arranged on the main surface of a circuit board 21b (substrate). The plurality of lenses 261 correspond to the plurality of light-emitting elements 21a. Each of the plurality of lenses 261 has an incident surface 263a, 264a, an exit surface 263c, 264c, and a reflecting surface 263b, 264b (see FIGS. 4 and 5). The incident surfaces 263a, 264a face the corresponding light-emitting elements 21a (see FIGS. 4 and 5). The incident surfaces 263a, 264a are concave (see FIGS. 4 and 5). The exit surfaces 263c, 264c are arranged on the side opposite to the incident surfaces 263a, 264a (see FIGS. 4 and 5). The reflecting surfaces 263b, 264b connect the ends of the incident surfaces 263a, 264a and the ends of the exit surfaces 263c, 264c (see FIGS. 4 and 5). The plurality of light-emitting elements 21a include a first light-emitting element 21c and a second light-emitting element 21d. The first light-emitting element 21c has a first optical axis G1c. The second light-emitting element 21d has a second optical axis G1d. The plurality of lenses 261 include a first lens 263 and a second lens 264. The first lens 263 corresponds to the first light-emitting element 21c and emits light upward from the first luminance maximum direction. The first luminance maximum direction is a light distribution direction in which the luminance of the combined light of the light emitted from each of the plurality of lenses 261 becomes the maximum luminance. The second lens 264 corresponds to the second light-emitting element 21d and emits light downward from a direction lower than the first luminance maximum direction. The first ratio is larger than the second ratio. The first ratio is the ratio of the height L10 in the direction of the first optical axis G1c in the first lens 263 to the first light-emitting area H10 of the first light-emitting element 21c (see FIG. 12). The second ratio is the ratio of the height L11 in the direction of the second optical axis G1d in the second lens 264 to the second light-emitting area H11 of the second light-emitting element 21d. The first light-emitting area H10 of the first light-emitting element 21c is smaller than the second light-emitting area H11 of the second light-emitting element 21d (see FIG. 12).

[0012] In this configuration, the first ratio is greater than the second ratio, and the first light-emitting area H10 of the first light-emitting element 21c is smaller than the second light-emitting area H11 of the second light-emitting element 21d (Configuration 1). With Configuration 1, a steep cut-off line KL1 can be set on the upper side of the first maximum brightness direction of the combined light (illumination light) of the combined light emitted from each of the multiple lenses 261 (see Figure 7). Furthermore, with Configuration 1, the multiple lenses 261 can be housed within the area of ​​the main surface of the circuit board 21b (substrate area), thereby ensuring the luminous flux required for illumination. Thus, it is possible to set a steep cut-off line on the upper side of the first maximum brightness direction of the illumination light while ensuring the luminous flux required for illumination with a limited substrate area.

[0013] (2) Overall structure Referring to Figures 1 to 12, the lighting device 1 according to Embodiment 1 will be described. The lighting device 1 is a floodlight used for illuminating (floodlighting) outdoor areas. More specifically, the lighting device 1 is used, for example, to illuminate (floodlight) various sports fields (such as soccer stadiums), school playgrounds, or parking lots.

[0014] In the following explanation, unless otherwise specified, the front, back, left, right, and up and down directions of the lighting device 1 in Figure 1 are defined as follows: the side with the cover 3 of the lighting device 1 is the front, and the side with the heat sink 6 is the rear. Also, when viewed from the front of the lighting device 1, the top is the top, the bottom is the bottom, the left side is the left, and the right side is the right.

[0015] As shown in Figure 1, the lighting device 1 comprises a lighting device body 102, a fixing member 103, a support member 104, a power supply box 105, and a wiring box 106.

[0016] The lighting device body 102 emits illumination light. The lighting device body 102 comprises a plurality of (two in Figure 1) illumination units SU1 and a pair of connecting parts 107. The plurality of illumination units SU1 emit illumination light. The pair of connecting parts 107 connects the plurality of illumination units SU1 in a vertically aligned manner. More specifically, the pair of connecting parts 107 connects the right ends of the plurality of illumination units SU1 to each other and the left ends to each other.

[0017] The fixing member 103 secures the power box 105 to the back of the lighting device body 102. The fixing member 103 is mounted across a pair of left and right connecting parts 107. The fixing member 103 is positioned to wrap around from the pair of left and right connecting parts 107 to the rear of the lighting device body 102.

[0018] The support member 104, when installed in a designated location such as a stadium, supports the lighting device body 102 so that it can rotate around a rotation axis RG1 extending in the left-right direction. The support member 104 is mounted across a pair of left and right connecting parts 107. The support member 104 is positioned to wrap around from the pair of left and right connecting parts 107 to the rear lower side of the lighting device body 102.

[0019] The power box 105 is a part that includes a power supply circuit that converts AC power supplied via the junction box 106 into DC power and supplies it to the lighting device body 102. The power box 105 is fixed to the rear side of the lighting device body 102 by a fixing member 103.

[0020] The junction box 106 is the part to which power lines from an external AC power source (e.g., grid power) are connected. The junction box 106 supplies AC power from the external AC power source to the power circuit of the power box 105. The junction box 106 is fixed to the rear side of the power box 105.

[0021] In this lighting device 1, illumination light is emitted forward from the front side of the lighting device body 102. The illumination light is emitted approximately in the direction of the optical axis CG1 of the lighting device 1. The optical axis CG1 is parallel to the normal of the front surface 102a of the lighting device body 102. The front surface 102a is the front surface of the cover 3 of the lighting unit SU1. In this lighting device 1, the direction of illumination light emission (direction of the optical axis CG1) can be changed vertically by rotating the lighting device body 102 around the rotation axis RG1. This lighting device 1 can be installed, for example, in a relatively high place and emits illumination light from above in a diagonal downward direction to illuminate, for example, the ground of a sports field.

[0022] In this lighting device 1, the illumination light is distributed such that it has a steep cut-off line KL1 above the optical axis CG1 (more specifically, above the direction of maximum brightness of the illumination light) (see Figure 8). The cut-off line is the direction of light distribution in which the brightness of the illumination light decreases sharply and falls below a predetermined brightness. In Embodiment 1, the first direction of maximum brightness is assumed to be above the direction of the optical axis CG1, but it may be the same direction as the optical axis CG1, or below the direction of the optical axis CG1. In Figure 8, the vertical axis represents the brightness of the illumination light, the horizontal axis represents the direction of light distribution of the illumination light, 0 degrees on the horizontal axis represents the first direction of maximum brightness, the + side of the horizontal axis is the upper side, and the - side is the lower side.

[0023] As described above, the illumination light from the lighting device 1 is distributed such that it has a steep cut-off line KL1 above the optical axis CG1 (more specifically, above the direction in which the illumination light's brightness is maximum), thus preventing the illumination light from traveling unnecessarily far. In addition, the illumination light is distributed such that the brightness of the light emitted above the optical axis CG1 is sufficient (for example, enough brightness to make a ball visible when it flies over the field at night).

[0024] (3) Lighting unit As shown in Figures 2 and 3, the lighting unit SU1 comprises a light source unit 2, a cover 3, a waterproof packing 4, a retaining member 5, and a heat sink 6.

[0025] The light source unit 2 constitutes the light source of the lighting device 1. The light source unit 2 is located on the front surface 61s of the heat sink 6. The light source unit 2 comprises a light-emitting module 21, a heat-conducting sheet 23, and a lens block 26.

[0026] The light-emitting module 21 has a plurality of light-emitting elements 21a and a circuit board 21b.

[0027] Each of the multiple light-emitting elements 21a is, for example, a white light-emitting diode that emits white light to serve as illumination light. The circuit board 21b is, for example, a rectangular flat plate. The multiple light-emitting elements 21a are provided on the front surface of the circuit board 21b and are electrically connected to a wiring conductor formed on the front surface of the circuit board 21b. The multiple light-emitting elements 21a are arranged vertically and horizontally on the front surface of the circuit board 21b with spacing between them.

[0028] The light-emitting module 21 is fixed to the front surface 61s of the heat sink 6 via a thermal conductive sheet 23. In Embodiment 1, multiple fixing pieces are stacked on multiple locations around the periphery of the circuit board 21b and fixed to the heat sink 6 with screws. In this way, the periphery of the circuit board 21b is sandwiched between the fixing pieces and the heat sink 6, thereby fixing the light-emitting module 21 to the front surface 61s of the heat sink 6.

[0029] The thermal conductive sheet 23 is a component that efficiently conducts heat generated in the light-emitting module 21 from the circuit board 21b to the heat sink 6. The thermal conductive sheet 23 is placed between the light-emitting module 21 and the heat sink 6. The thermal conductive sheet 23 is formed, for example, in the shape of a rectangular sheet. The planar size of the thermal conductive sheet 23 is, for example, about the same as the planar size of the light-emitting module 21. The thermal conductive sheet 23 is formed of a material having electrical insulation and thermal conductivity (for example, an elastomer material, silicone gel, or acrylic resin containing a filler).

[0030] The lens block 26 is a component that controls the light distribution of the light emitted from the light-emitting element 21a. This control ensures that a steep cut-off line KL1 is formed above the optical axis CG1 of the illumination device 1 (more specifically, above the direction of maximum brightness of the illumination light). The lens block 26 is positioned in front of the light-emitting module 21 (i.e., facing the light-emitting module 21).

[0031] The lens block 26 has a plurality of lenses 261 and a connecting portion 262. The plurality of lenses 261 and the connecting portion 262 are integrally molded from a translucent synthetic resin such as acrylic resin, polycarbonate resin, or ABS resin.

[0032] Multiple lenses 261 correspond one-to-one with multiple light-emitting elements 21a and are arranged facing the front of the corresponding light-emitting elements 21a. The multiple lenses 261 include a first lens 263 (see Figure 4) and a second lens 264 (see Figure 5). In the lens block 26, the first lens 263 and the second lens 264 are arranged alternately, for example. Hereinafter, the light-emitting element 21a corresponding to the first lens 263 will be referred to as the first light-emitting element 21c, and the light-emitting element 21a corresponding to the second lens 264 will be referred to as the second light-emitting element 21d. The first lens 263 emits light emitted by the first light-emitting element 21c upwards from the optical axis CG1 of the illumination light of the lighting device 1 (more specifically, for example, upwards from the first direction of maximum brightness). The second lens 264 emits light emitted by the second light-emitting element 21d downwards from the optical axis CG1 of the illumination light of the lighting device 1 (more specifically, for example, downwards from the first direction of maximum brightness). The specific shapes of the first lens 263 and the second lens 264 will be described later.

[0033] The connecting portion 262 connects the multiple lenses 261. The connecting portion 262 is, for example, a rectangular plate. The multiple lenses 261 are connected to the connecting portion 262 in a manner that penetrates through the connecting portion 262 in the thickness direction. In other words, the multiple lenses 261 are connected to the connecting portion 262 such that, for example, the front part protrudes forward from the front surface of the connecting portion 262 and the rear part protrudes backward from the rear surface of the connecting portion 262. The connecting portion 262 is fixed to the heat sink 6 via multiple support members so that the lens block 26 is positioned on the front side of the heat sink 6. In this fixed state, the lens block 26 is positioned on the front side of the light-emitting module 21 which is fixed to the front surface of the heat sink 6.

[0034] The heat sink 6 is a component that dissipates heat generated by the light-emitting module 21 to the outside. The heat sink 6 is made of a thermally conductive material (for example, metal, specifically aluminum or an aluminum alloy). The heat sink 6 has a base portion 61 and a plurality of heat dissipation fins 62. The base portion 61 and the plurality of heat dissipation fins 62 are integrally molded. The base portion 61 is, for example, a rectangular flat plate. The base portion 61 has a front surface 61s and a rear surface 61k. The rear surface 61k is the main surface opposite the front surface 61s. Each heat dissipation fin 62 is, for example, formed in the shape of a rectangular thin plate. The plurality of heat dissipation fins 62 protrude rearward from the rear surface 61k of the base portion 61. The plurality of heat dissipation fins 62 are arranged with their thickness directions aligned in the left-right direction and spaced apart from each other.

[0035] Cover 3 is a component that covers the light source unit 2. Cover 3 is a roughly rectangular box shape with an open rear surface. Cover 3 is fixed to the front surface 61s of the heat sink 6. Cover 3 is made of a light-transmitting resin material (for example, acrylic resin or polycarbonate resin) that allows light emitted from the light-emitting element 21a to pass through. This allows light emitted from the light source unit 2 to pass through. Cover 3 has a cover body 31 and a flange portion 32. The cover body 31 and the flange portion 32 are integrally molded. Cover body 31 is formed in a roughly rectangular box shape with an open rear surface. Cover body 31 includes a front surface 102a and an upper wall 31u. The flange portion 32 protrudes outward around the entire circumference from the periphery of the rear opening of the cover body 31. The flange portion 32 is formed in the shape of a rectangular frame, which is approximately the same shape and size as the front surface 61s and periphery of the heat sink 6 (see Figure 3).

[0036] The retaining member 5 is a member that fixes the cover 3 to the front surface 61s of the heat sink 6. The retaining member 5 is a rectangular frame shape approximately the same size as the flange portion 32 of the cover 3 (see Figure 3). The retaining member 5 is made of a metal plate (for example, a stainless steel plate). The retaining member 5 is fixed to the front surface 61s of the heat sink 6 with screws or the like, with the flange portion 32 of the cover 3 sandwiched between the retaining member 5 and the periphery of the front surface 61s of the heat sink 6.

[0037] The waterproof packing 4 is a component that seals the space between the flange 32 of the cover 3 and the heat sink 6, and between the flange 32 of the cover 3 and the retaining member 5. The waterproof packing 4 is formed in a rectangular frame shape from an electrically insulating elastic material (for example, silicone rubber). The waterproof packing 4 is placed between the flange 32 of the cover 3 and the heat sink 6, and between the flange 32 of the cover 3 and the retaining member 5.

[0038] (4) Details of the first and second lenses Next, the shapes of the first lens 263 and the second lens 264 will be described in detail with reference to Figures 4 and 5.

[0039] In the following description, the optical axis of the light-emitting element 21a is denoted as G1. When distinguishing between the optical axes G1 of the first light-emitting element 21c and the second light-emitting element 21d, the optical axis G1 of the first light-emitting element 21c is referred to as the first optical axis G1c, and the optical axis G1 of the second light-emitting element 21d is referred to as the second optical axis G1d. The optical axis G1 is fixed to the light-emitting element 21a. The optical axis G1 coincides with the front-to-back direction, which is the normal direction of the circuit board 21b. Therefore, the optical axes G1 of each of the multiple light-emitting elements 21a are parallel to each other.

[0040] As shown in Figure 4, the first lens 263 has an incident surface 263a, a reflective surface 263b, and an exit surface 263c.

[0041] The incident surface 263a is a concave incident surface facing the corresponding first light-emitting element 21c. More specifically, the incident surface 263a is the surface to which the emitted light from the first light-emitting element 21c is incident. The incident surface 263a is positioned in front of the first light-emitting element 21c. The incident surface 263a is formed by the rear surface of the first lens 263. The incident surface 263a is concave (for example, a bottomed cylindrical concave) that is recessed towards the front (towards the emitted surface 263c).

[0042] The incident surface 263a includes a first incident surface 263d and a second incident surface 263e. The first incident surface 263d is formed by the bottom surface of the incident surface 263a and is formed, for example, as a convex curved surface projecting backward to guide the light emitted from the first light-emitting element 21c to the exit surface 263c. The second incident surface 263e is formed by the inner circumferential surface of the incident surface 263a and is an incident surface capable of guiding the light emitted from the first light-emitting element 21c that does not enter the first incident surface 263d to the exit surface 263c.

[0043] The reflective surface 263b connects the end of the incident surface 263a and the end of the exit surface 263c. More specifically, the reflective surface 263b is formed by the outer circumferential surface of the first lens 263. The reflective surface 263b is formed as a convex curved surface that protrudes backward, with its vertical and horizontal widths gradually increasing from the rear to the front of the first lens 263. The reflective surface 263b is a reflective surface that reflects light incident on the second incident surface 263e and guides it to the exit surface 263c.

[0044] The emission surface 263c is located on the opposite side from the incidence surface 263a in the direction of the optical axis G1c of the first light-emitting element 21c. More specifically, the emission surface 263c is formed by the front surface of the first lens 263. The emission surface 263c is the surface that emits light that has passed through the first lens 263 to the outside of the first lens 263. The emission surface 263c is, for example, an elliptical plane.

[0045] The first lens 263 is formed in a shape that is asymmetrical in the vertical direction with respect to the optical axis G1c of the first light-emitting element 21c, such that the light emitted from the first lens 263 is emitted above the optical axis G1c of the first light-emitting element 21c. More specifically, for example, the inclination of the upper part of the reflective surface 263b is steeper than the inclination of the lower part of the reflective surface 263b, and the center of the emission surface 263c is shifted above the optical axis G1c of the first light-emitting element 21c.

[0046] As shown in Figure 5, the second lens 264 has an incident surface 264a, a reflective surface 264b, and an exit surface 264c.

[0047] The incident surface 264a is a concave incident surface facing the corresponding second light-emitting element 21d. More specifically, the incident surface 264a is the surface to which the emitted light from the second light-emitting element 21d is incident. The incident surface 264a is positioned in front of the second light-emitting element 21d. The incident surface 264a is formed by the rear surface of the second lens 264. The incident surface 264a is concave (for example, a bottomed cylindrical concave) that is recessed towards the front (towards the emitted surface 264c).

[0048] The incident surface 264a includes a third incident surface 264d and a fourth incident surface 264e. The third incident surface 264d is formed by the bottom surface of the incident surface 264a and is formed, for example, as a convex curved surface projecting backward to guide the light emitted from the second light-emitting element 21d to the exit surface 264c. The fourth incident surface 264e is formed by the inner circumferential surface of the incident surface 264a and is an incident surface capable of guiding the light emitted from the second light-emitting element 21d that does not enter the third incident surface 264d to the exit surface 264c. The fourth incident surface 264e is circumferential in shape.

[0049] The reflective surface 264b connects the end of the incident surface 264a and the end of the exit surface 264c. More specifically, the reflective surface 264b is formed by the outer circumferential surface of the second lens 264. The reflective surface 264b is formed as a convex curved surface that protrudes backward, with its diameter gradually increasing from the rear to the front of the second lens 264. The reflective surface 264b is a reflective surface that reflects light incident on the fourth incident surface 264e and guides it to the exit surface 264c.

[0050] The emission surface 264c is located on the opposite side from the incidence surface 264a in the direction of the optical axis G1d of the second light-emitting element 21d. More specifically, the emission surface 264c is formed by the front surface of the second lens 264. The emission surface 264c is the surface that emits light that has passed through the second lens 264 to the outside of the second lens 264. The emission surface 264c is, for example, a plane.

[0051] The second lens 264 is formed in a shape that is asymmetrical in the vertical direction with respect to the optical axis G1 of the first light-emitting element 21c, such that the light emitted from the second lens 264 is emitted below the optical axis G1 of the second light-emitting element 21d. More specifically, for example, the inclination of the upper part of the reflective surface 264b is steeper than the inclination of the lower part of the reflective surface 264b, and the center of the emission surface 264c is shifted below the optical axis G1d of the second light-emitting element 21d.

[0052] (5) An example of the propagation of light emitted from a light-emitting element Next, with reference to Figures 6 and 7, an example of how the light emitted from the light-emitting element 21a propagates will be explained.

[0053] As shown in Figure 6, the light emitted from the first light-emitting element 21c is incident on the first incident surface 263d and the second incident surface 263e.

[0054] Light incident on the first incident surface 263d passes through the exit surface 263c of the first lens 263 and the cover 3 (see Figure 3) and is emitted as light C2. Light C2 is emitted, for example, upward with respect to the optical axis G1c.

[0055] Light incident on the second incident surface 263e is reflected by the reflective surface 263b of the first lens 263, passes through the exit surface 263c of the first lens 263 and the cover 3 (see Figure 3), and is emitted as light C1. The brightness of light C1 is greater than or equal to the brightness of light C2. In other words, light C1 is 50% or more of the light incident on the first lens 263 from the first light-emitting element 21c. Light C1 is a parallel ray. Here, light C1 being a parallel ray means that light C1 can be considered as light emitted from a hypothetical light source located at infinity. The beam divergence angle of light C1 is, for example, 2 degrees or less. Light C1 is emitted upward with respect to the optical axis G1c. In this embodiment, the angle θ1 between the direction of propagation of light C1 and the optical axis G1 is, for example, 5 degrees or more.

[0056] In other words, light C1 is the light emitted from the illumination device 1 that is emitted above the optical axis CG1. By appropriately designing the reflective surface 263b of the first lens 263, it is easy to prevent light C1 from leaking above the direction of the optical axis CG1. The brightness of the light emitted above the optical axis CG1 becomes greater than the brightness of the light emitted below the optical axis CG1.

[0057] Furthermore, as shown in Figure 7, light from the second light-emitting element 21d is incident on the third incident surface 264d and the fourth incident surface 264e.

[0058] Light incident on the third incident surface 264d passes through the exit surface 264c of the second lens 264 and the cover 3 (see Figure 3) and is emitted as light C4. Light C4 is emitted, for example, downward with respect to the optical axis G1.

[0059] Light incident on the fourth incident surface 264e is reflected by the reflective surface 264b of the second lens 264, passes through the exit surface 264c of the second lens 264 and the cover 3 (see Figure 3), and is emitted as light C3. Light C3 is a substantially parallel ray. Light C3 is emitted downward with respect to the optical axis G1.

[0060] In other words, light C3 and light C4 are the light emitted from the illumination device 1 that is emitted below the optical axis G1. Therefore, in the illumination device 1, the brightness of the illumination light emitted below the optical axis CG1 can be made sufficiently large. Furthermore, by appropriately designing the shape of the second lens 264 and controlling the propagation direction and brightness of light C3 and light C4, the light distribution characteristics below the optical axis CG1 can be easily controlled in the illumination device 1.

[0061] Furthermore, in the lighting device 1, the light emitted from the first light-emitting element 21c passes through the first lens 263, then through the cover 3, and is emitted outside the lighting device 1. Also, in the lighting device 1, the light emitted from the second light-emitting element 21d passes through the second lens 264, then through the cover 3, and is emitted outside the lighting device 1. In other words, in the lighting device 1, the light emitted from the light-emitting element 21a passes through one lens 261, then through the cover 3, and is emitted outside the lighting device 1. To put it another way, in the lighting device 1, the light emitted from the light-emitting element 21a does not pass through two different lenses. Therefore, stray light can be reduced, and the reduction in illumination light can be suppressed.

[0062] (6) Light distribution characteristics of lighting devices Next, with reference to Figure 8, the light distribution characteristics Q0 of the illumination device 1 will be described.

[0063] In Figure 8, the vertical axis represents the luminance of the light emitted by lighting device 1, and the horizontal axis represents the vertical beam angle of the light emitted by lighting device 1. The vertical axis uses a logarithmic scale. The unit of the horizontal axis is angles. On the horizontal axis, 0 degrees represents the direction of maximum luminance of the light emitted by lighting device 1 (first maximum luminance direction), the positive side of the horizontal axis corresponds to the area above the first maximum luminance direction, and the negative side of the horizontal axis corresponds to the area below the first maximum luminance direction.

[0064] In the illumination light, the luminance of the light emitted in the -15 degree direction is defined as luminance M1, the luminance of the light emitted in the +15 degree direction is defined as luminance M2, and the luminance of the light emitted in the +60 degree direction is defined as luminance M3.

[0065] The illumination light from the illumination device 1 is a composite of light C1 and C2 emitted upward from the first maximum brightness direction (i.e., the 0-degree direction) after passing through the first lens 263 from the first light-emitting element 21c, and light C3 and C4 emitted downward from the second lens 264 from the second light-emitting element 21d, below the first maximum brightness direction. More specifically, it is preferable that the lens 261 is configured such that the ratio of brightness M2 to brightness M1 is 0.1 or less. Furthermore, it is preferable that the lens 261 is configured such that brightness M3 is smaller than brightness M2. In the example of Figure 8, a cut line KL1 is formed in the +15-degree direction. The cut line KL1 is the light distribution direction in which the brightness decreases to a predetermined brightness (for example, M2 in the example of Figure 8). In the example of Figure 8, the brightness decreases sharply from M1 to M2 at the cut line KL1. That is, above the cut line KL1, the brightness is limited to M2 or less.

[0066] Thus, the light distribution characteristics Q0 of the illumination device 1 have a steep cut-off line KL1 on the upper side of the first maximum brightness direction of the illumination light (for example, a 15-degree light distribution direction).

[0067] (7) Differences in cut lines due to the relative size relationship between the light-emitting element and the lens. Consider the combination of the light-emitting element 21a and the lens 100 shown in Figure 9. In the example in Figure 9, the lens 100 is positioned in front of the light-emitting element 21a. The light emitted from the light-emitting element 21a passes through the lens 100 and is emitted as light C10.

[0068] Lens 100 has an incident surface 111, an exit surface 112, and a reflecting surface 113. The incident surface 111 is a concave incident surface facing the light-emitting element 21a. The exit surface 112 is located on the opposite side from the incident surface 111. The reflecting surface 113 connects the end of the incident surface 111 and the end of the exit surface 112. The optical axis (central axis) of lens 100 coincides with the optical axis G1 of the light-emitting element 21a, and lens 100 has a shape that is vertically symmetrical with respect to the optical axis G1. The first lens 263 is a lens obtained by deforming lens 100 into a shape that is vertically asymmetrical with respect to the optical axis G1 of the corresponding light-emitting element 21a, such that the light emitted from lens 100 is emitted above the optical axis G1. For example, the first lens 263 is a lens obtained by deforming the lower half of lens 100 to the shape T1. The second lens 264 is a lens obtained by deforming lens 100 into a shape that is asymmetrical in the vertical direction with respect to the optical axis G1 of the corresponding light-emitting element 21a, such that the light emitted from lens 100 is emitted below the optical axis G1. For example, the second lens 264 is a lens obtained by inverting the first lens 263 vertically.

[0069] In Figure 9, consider the case where the light-emitting area of ​​the light-emitting element 21a is changed to different sizes H1 to H4. During this change, the relative position and center position of the light-emitting element 21a with respect to the lens 100 are fixed. The sizes H1 to H4 increase in the vertical direction as you move from size H1 to size H4. Note that sizes H1 to H4 can also be described as the vertical width of the light-emitting area of ​​the light-emitting element 21a. In the example in Figure 9, only the light-emitting element 21a for size H1 is shown, and the light-emitting elements 21a for sizes H2 to H4 are omitted from the illustration.

[0070] Figure 10 shows the light distribution characteristics Q1 to Q4 of the light emitted C10 from lens 100 when the light-emitting area size of the light-emitting element 21a is H1 to H4. In other words, the light distribution characteristics Q1 to Q4 correspond to the light distribution characteristics of sizes H1 to H4.

[0071] As can be seen from Figures 9 and 10, the smaller the size of the light-emitting area H1 to H4 of the light-emitting element 21a, the narrower the width of the light distribution above a certain brightness M4, and the steeper the cut-off line (i.e., the cut-off line where brightness decreases more rapidly) of the light distribution characteristics Q1 to Q4. More specifically, light distribution characteristic Q1 has the narrowest width of the light distribution above a certain brightness M4, and therefore has the steepest cut-off line (i.e., the cut-off line where brightness decreases most rapidly) KL2. Light distribution characteristic Q4 has the widest width of the light distribution above a certain brightness M4, and therefore has the gentlest cut-off line (i.e., the cut-off line where brightness decreases most gradually) KL3. Note that the cut-off lines of light distribution characteristics Q1 and Q4 occur on both the + and - sides of the light distribution direction, but in the example in Figure 10, only the cut-off lines KL2 and KL3 on the + side of the light distribution direction are shown, and the cut-off line on the - side of the light distribution direction is omitted from the illustration. Note that the cut-off lines for the light distribution characteristics Q2 and Q3 are also omitted from the illustration. Thus, the smaller the size H1 to H4, the steeper the cut-off lines obtained for the light distribution characteristics Q1 to Q4.

[0072] From the above, if the lenses 100 are of the same shape and size, the smaller the size H1 to H4 of the light-emitting area of ​​the light-emitting element 21a, the steeper the cut-off line of the light distribution characteristics Q1 to Q4 of the lens 100 will be. In other words, if the size of the light-emitting area of ​​the light-emitting element 21a is the same, the shape of the lens 100 is the same, and the larger the relative size of the lens 100 (e.g., the emission surface 112 and height 114), the steeper the cut-off line of the light distribution characteristics Q1 to Q4 of the light emitted by the lens 100 will be. Thus, it is possible to give the light distribution characteristics Q1 to Q4 of the light emitted by the lens 100 a steeper cut-off line depending on the relative size of the lens 100 with respect to the light-emitting area of ​​the light-emitting element 21a (e.g., the emission surface 112 and height 114). Note that the height 114 is the length of the lens 100 in the direction of the optical axis G1 of the light-emitting element 21a.

[0073] This relationship is also applicable to the first lens 263 and the second lens 264. By increasing the ratio of the relative size of the first lens 263 to the light-emitting area H10 of the first light-emitting element 21c (for example, the height L10 of the first lens 263), it is possible to give the light distribution characteristic Q10 of the light emitted from the first lens 263 a steeper cut-off line. Similarly, by decreasing the relative size of the second lens 264 to the light-emitting area H11 of the second light-emitting element 21d (for example, the height L11 of the second lens 264), it is possible to prevent the light distribution characteristic Q11 of the light emitted from the second lens 264 from having a steep cut-off line.

[0074] (8) Individual light distribution characteristics of the first and second lenses As shown in Figure 11, the light distribution characteristics Q0 of the illumination light of the illumination device 1 are formed by combining the light distribution characteristics Q10 of the light emitted from the first lens 263 and the light distribution characteristics Q11 of the light emitted from the second lens 264.

[0075] Of the light distribution characteristics Q0 of the lighting device 1, the portion of the light distribution characteristics above the first maximum brightness direction (0-degree direction in Figure 11) (i.e., the portion of the light distribution characteristics having the cut-off line KL1) is composed of the light distribution characteristics Q10 of the first lens 263. More specifically, of the light distribution characteristics Q0 of the lighting device 1, the portion of the light distribution characteristics above the first maximum brightness direction (0-degree direction in Figure 11) is composed of the portion of the light distribution characteristics Q10 of the first lens 263 above the first maximum brightness direction. For this reason, as shown in Figure 12, the ratio of the relative size of the first lens 263 (for example, the height L10 of the first lens 263) to the light-emitting area H10 of the first light-emitting element 21c (more specifically, the vertical size of the light-emitting area H10) (hereinafter referred to as the "first ratio") is relatively large. More specifically, the first ratio is larger than the second ratio described later. As a result, the light distribution characteristic Q10 of the first lens 263 has a sharp cut-off line KL1 on the upper side of the first maximum brightness direction, and constitutes the portion of the light distribution characteristic Q0 of the lighting device 1 that is above the first maximum brightness direction.

[0076] In this case, the first lens 263 is formed asymmetrically in the vertical direction with respect to the optical axis G1c of the corresponding first light-emitting element 21c, thereby limiting the light distribution of the emitted light from the emission surface 263c to the upward direction from the first direction of maximum brightness. Furthermore, the light distribution characteristic Q10 of the first lens 263 has a steep cut-off line KL1 15 degrees upward from the first direction of maximum brightness of the illumination light, as the first ratio is greater than the second ratio. In Embodiment 1, the light-emitting area H10 of the first light-emitting element 21c (more specifically, the vertical size of the light-emitting area H10) is further smaller than the light-emitting area H11 of the second light-emitting element 21d (more specifically, the vertical size of the light-emitting area H11). As a result, the first ratio is even larger than the second, and the steepness of the cut-off line KL1 of the light distribution characteristic Q10 of the first lens 263 is further increased.

[0077] Furthermore, as shown in Figure 11, the portion of the light distribution characteristic Q0 of the lighting device 1 that is below the first maximum brightness direction (0-degree direction in Figure 11) (i.e., the portion of the light distribution characteristic that does not have a cut line steeper than the cut line KL1) is mainly composed of the light distribution characteristic Q11 of the second lens 264. More specifically, the portion of the light distribution characteristic Q0 of the lighting device 1 that is below the first maximum brightness direction is composed of a combination of the portion of the light distribution characteristic Q10 of the first lens 263 that is below the first maximum brightness direction (0-degree direction in Figure 11) and the light distribution characteristic Q11 of the second lens 264. For this reason, as shown in Figure 12, the ratio of the relative size of the second lens 264 (for example, the height L11 of the second lens 264) to the light emission area H11 of the second light-emitting element 21d (more specifically, the vertical size of the light emission area H11) (hereinafter referred to as the "second ratio") is relatively small. More specifically, the second ratio is smaller than the first ratio. As a result, the light distribution characteristic Q11 of the second lens 264 does not have a cut-off line steeper than the cut-off line KL1 below the second maximum brightness direction of the light distribution characteristic Q11. The second maximum brightness direction is the direction in which the brightness of the light distribution characteristic Q11 is at its maximum brightness.

[0078] In this case, the second lens 264 is formed asymmetrically in the vertical direction with respect to the optical axis G1d of the corresponding second light-emitting element 21d, thereby limiting the light distribution of the emitted light from the emission surface 263c to the downward side. Furthermore, the light distribution characteristic Q11 of the second lens 264 has a second ratio smaller than the first ratio, and therefore does not have a cut-off line steeper than the cut-off line KL1. In Embodiment 1, the light-emitting area H11 of the second light-emitting element 21d (more specifically, the vertical size of the light-emitting area H11) is also larger than the light-emitting area H10 of the first light-emitting element 21c (more specifically, the vertical size of the light-emitting area H10). As a result, the second ratio becomes even smaller than the first ratio, and the steepness of the cut-off line of the light distribution characteristic Q11 of the second lens 264 is further reduced.

[0079] In Embodiment 1, since the first ratio is greater than the second ratio, the emission surface 263c of the first lens 263 is larger than the emission surface 264c of the second lens 264, and the height L10 of the first lens 263 is larger than the height L11 of the second lens 264 (see Figure 12). Furthermore, since the light-emitting area H10 of the first light-emitting element 21c is smaller than the light-emitting area H11 of the second light-emitting element 21d, the emission surface 263c of the first lens 263 is even larger than the emission surface 264c of the second lens 264, and the height L10 of the first lens 263 is even larger than the height L11 of the second lens 264.

[0080] (9) Examples of arrangements of the first and second lenses As shown in Figure 13, the first lens 263 and the second lens 264 are arranged alternately in the vertical and horizontal directions. That is, the first lens 263 and the second lens 264 are arranged alternately in the vertical direction, and the first lens 263 and the second lens 264 are arranged alternately in the horizontal direction. In Embodiment 1, the emission surface 263c of the first lens 263 is formed to be relatively large, while the emission surface 264c of the second lens 264 is formed to be relatively small. Therefore, the multiple lenses 261 consisting of the first lens 263 and the second lens 264 can be arranged within the area of ​​the main surface (substrate area) of the circuit board 21b without overflowing. That is, there is no need to reduce the number of multiple lenses 261, and therefore there is no need to reduce the number of multiple light-emitting elements 21a. For this reason, the number of lenses 261 necessary to secure the luminous flux required for the illumination light of the lighting device 1 can be arranged within the area of ​​the main surface (substrate area) of the circuit board 21b. Note that in Figure 13, only the lenses 261 of the lens block 26 are shown, and the connecting portion 262 is omitted from the illustration.

[0081] (10) Effects The illumination device 1 according to Embodiment 1 comprises a plurality of light-emitting elements 21a and a plurality of lenses 261. The plurality of light-emitting elements 21a are arranged on the main surface of the circuit board 21b. The plurality of lenses 261 correspond to the plurality of light-emitting elements 21a. Each of the plurality of lenses 261 has an incident surface 263a, 264a, an exit surface 263c, 264c, and a reflecting surface 263b, 264b. The incident surfaces 263a, 264a are concave. The incident surfaces 263a, 264a face the corresponding light-emitting elements 21a. The reflecting surfaces 263b, 264b connect the ends of the incident surfaces 263a, 264a and the ends of the exit surfaces 263c, 264c. The plurality of light-emitting elements 21a include a first light-emitting element 21c and a second light-emitting element 21d. The first light-emitting element 21c has a first optical axis G1c. The second light-emitting element 21d has a second optical axis G1d. The plurality of lenses 261 include a first lens 263 and a second lens 264. The first lens 263 corresponds to the first light-emitting element 21c and emits light upward from a first brightness maximum direction, which is the light distribution direction in which the brightness of the combined light emitted from each of the plurality of lenses 261 is maximized. The second lens 264 corresponds to the second light-emitting element 21d and emits light downward from the first brightness maximum direction. The first ratio is greater than the second ratio. The first ratio is the ratio of the height L10 in the direction of the first optical axis G1c in the first lens 263 to the first light-emitting area H10 of the first light-emitting element 21c. The second ratio is the ratio of the height L11 in the direction of the second optical axis G1d in the second lens 264 to the second light-emitting area H11 of the second light-emitting element 21d. The first light-emitting area H10 of the first light-emitting element 21c is smaller than the second light-emitting area H11 of the second light-emitting element 21d.

[0082] In this configuration, the first ratio is greater than the second ratio, and the first light-emitting area H10 of the first light-emitting element 21c is smaller than the second light-emitting area H11 of the second light-emitting element 21d (Configuration 1). With Configuration 1, a steep cut-off line KL1 can be set on the upper side of the first maximum brightness direction of the combined light (illumination light) of the combined light emitted from each of the multiple lenses 261. Furthermore, with Configuration 1, the multiple lenses 261 can be housed within the area of ​​the main surface of the circuit board 21b (substrate area), thereby ensuring the luminous flux required for illumination. Thus, it is possible to set a steep cut-off line KL1 on the upper side of the first maximum brightness direction of the illumination light while ensuring the luminous flux required for illumination with a limited substrate area.

[0083] Furthermore, in the illumination device 1 according to Embodiment 1, the light distribution characteristic Q0 of the combined light emitted from each of the multiple lenses 261 has a cut line KL1 in the light distribution direction 15 degrees above the first maximum brightness direction. With this configuration, it is possible to restrict the emission of illumination light in the combined light, i.e., illumination light, from the combined light emitted from each of the multiple lenses 261, to a direction above the light distribution direction 15 degrees above the first maximum brightness direction.

[0084] (11) Variant The following lists some modifications of Embodiment 1. The modifications described below can be combined and applied as appropriate.

[0085] (Variation 1) Referring to Figures 14 and 15, the lighting device 1 according to Modification 1 will be described.

[0086] As shown in Figure 14, in the lighting device 1 according to Modification 1, the height L10 of the first lens 263 and the height L11 of the second lens 264 are the same height, and the light-emitting area H10 of the first light-emitting element 21c (more specifically, the vertical size of the light-emitting area H10) is smaller than the light-emitting area H11 of the second light-emitting element 21d (more specifically, the vertical size of the light-emitting area H11). Thus, similar to the case of Embodiment 1, a steep cut-off line KL1 (see Figure 8) is formed on the upper side of the first maximum brightness direction of the illumination light of the lighting device 1.

[0087] As described above, when the height L10 of the first lens 263 and the height L11 of the second lens 264 are the same, and the light-emitting area H10 of the first light-emitting element 21c is smaller than the light-emitting area H11 of the second light-emitting element 21d, then, similar to Embodiment 1, the first ratio (i.e., the ratio of the height L10 of the first lens 263 to the light-emitting area H10 of the first light-emitting element 21c) is greater than the second ratio (i.e., the ratio of the height L11 of the second lens 264 to the light-emitting area H11 of the second light-emitting element 21d). Therefore, in Modification 1, similar to Embodiment 1, it is possible to form a steep cut-off line KL1 on the upper side of the first maximum brightness direction of the illumination light of the lighting device 1.

[0088] In the modified example 1, as shown in Figure 14, the connecting portion 262 of the lens block 26 is omitted, and the end of the first lens 263 on the exit surface 263c side and the end of the second lens 264 on the exit surface 264c side are integrally formed with the front wall portion 31f of the cover 3. The exit surface 263c of the first lens 263 and the exit surface 264c of the second lens 264 are flush with the front surface 102a of the front wall portion 31f of the cover 3.

[0089] As shown in Figure 15, in Modification 1, the first lens 263 and the second lens 264 are arranged alternately in the vertical and horizontal directions. That is, the first lens 263 and the second lens 264 are arranged alternately in the vertical direction, and the first lens 263 and the second lens 264 are arranged alternately in the horizontal direction. In Modification 1, the height L10 of the first lens 263 and the height L11 of the second lens 264 are the same height, so the emission surface 263c of the first lens 263 and the emission surface 264c of the second lens 264 are, for example, the same (or approximately the same) size as each other. In Modification 1, the emission area H10 of the first light-emitting element 21c is smaller than the emission area H11 of the second light-emitting element 21d, so the first ratio is made larger than the second ratio without increasing the respective sizes (emission surfaces 263c, 264c and heights L10, L11) of the first lens 263 and the second lens 264. Therefore, the multiple lenses 261, consisting of the first lens 263 and the second lens 264, can be arranged within the area of ​​the main surface (substrate area) of the circuit board 21b without overflowing. As a result, similar to Embodiment 1, the number of lenses 261 necessary to secure the luminous flux required for the illumination light of the lighting device 1 can be arranged within the area of ​​the main surface (substrate area) of the circuit board 21b.

[0090] According to Modification 1, the height L10 of the first lens 263 and the height L11 of the second lens 264 are the same, and the light-emitting area H10 of the first light-emitting element 21c is smaller than the light-emitting area H11 of the second light-emitting element 21d. Therefore, similar to the effect of Embodiment 1, it is possible to secure the luminous flux required for illumination with a limited substrate area while setting a steep cut-off line KL1 (see Figure 8) on the upper side of the first maximum brightness direction of the illumination light.

[0091] Furthermore, the lighting device 1 according to the modified example 1 further includes a cover 3. The cover 3 covers a plurality of light-emitting elements 21a and a plurality of lenses 261. The ends of each of the emission surfaces 263c, 264c of the plurality of lenses 261 are integrally formed with the front wall portion 31f of the cover 3. With this configuration, the plurality of lenses 261 and the cover 3 can be integrally formed. As a result, the number of parts of the lighting device 1 can be reduced and the lighting device 1 can be made thinner.

[0092] (Modification 2) In the modified example 2, the difference from embodiment 1 is that the plurality of light-emitting elements 21a include a third light-emitting element, and the plurality of lenses 261 further include a third lens corresponding to the third light-emitting element.

[0093] The optical axis of the third light-emitting element is parallel to the optical axis G1c of the first light-emitting element 21c (see Figure 4) and the optical axis G1c of the second light-emitting element 21d (see Figure 5). The third lens directs the light emitted from the third light-emitting element downwards from the first maximum brightness direction of the illumination light of the illumination device 1 (more specifically, downwards from the second maximum brightness direction of the light emitted from the second lens 264). The shape of the third lens is, for example, a lens modified so that the maximum brightness direction (second maximum brightness direction) of the light emitted from the second lens 264 is tilted further downwards.

[0094] As shown in Figure 16, in Modification 3, the light distribution characteristics Q0 of the illumination light of the illumination device 1 are composed of the light distribution characteristics Q10 of the light emitted from the first lens 263 (see Figure 4), the light distribution characteristics Q11 of the light emitted from the second lens 264 (see Figure 5), and the light distribution characteristics Q12 of the light emitted from the third lens. More specifically, the portion of the light distribution characteristics Q0 of the illumination light of the illumination device 1 that is above the first maximum brightness direction (0-degree direction in Figure 16) is composed of the light distribution characteristics Q10 of the first lens 263 (more specifically, the portion of the light distribution characteristics Q10 that is above the first maximum brightness direction (0-degree direction in Figure 16)). Furthermore, of the light distribution characteristics Q0 of the lighting device 1, the portion of the light distribution characteristics below the first maximum brightness direction (0-degree direction in Figure 16) is mainly composed of a combination of the light distribution characteristics Q11 of the second lens 264 and the light distribution characteristics Q12 of the third lens.

[0095] As described above, the direction of maximum brightness of the light emitted from the third lens (third maximum brightness direction) θ3 is inclined downwards compared to the direction of maximum brightness of the light emitted from the second lens 264 (second maximum brightness direction) θ2. Furthermore, the maximum brightness M21 of the light emitted from the third lens in the third maximum brightness direction θ3 is smaller than, for example, the maximum brightness M20 of the light emitted from the second lens in the second maximum brightness direction θ2. The second maximum brightness direction θ2 is the light distribution direction of the light emitted from the second lens 264 at which the brightness of the light emitted from the second lens reaches its maximum brightness M20, similar to the case of Embodiment 1. The third maximum brightness direction θ3 is the light distribution direction of the light emitted from the third lens at which the brightness of the light emitted from the third lens reaches its maximum brightness M21.

[0096] In the lighting device 1 according to Modification 2, the plurality of light-emitting elements 21a further include a third light-emitting element having a third optical axis. The plurality of lenses 261 further include a third lens. The third lens corresponds to the third light-emitting element and emits light downward from the first maximum brightness direction. The third maximum brightness direction θ3, where the brightness of the light emitted from the third lens is maximum, is directed downward from the second maximum brightness direction θ2, where the brightness of the light emitted from the second lens 264 is maximum. The maximum brightness M21 of the third lens in the third maximum brightness direction θ3 is smaller than the maximum brightness M20 of the second lens 264 in the second maximum brightness direction θ2. With this configuration, the light distribution characteristics downward from the first maximum brightness direction can be easily adjusted for the combined light (illumination light) of the light emitted from each of the plurality of lenses 261.

[0097] (Embodiment 2) (1) Composition The lighting device 1 according to Embodiment 2 will now be described.

[0098] In Embodiment 1, the first ratio was defined using "the height L10 of the first lens 263" as a specific example of the "relative size of the first lens 263" of the first ratio, and the second ratio was defined using "the height L11 of the second lens 264" as a specific example of the "relative size of the second lens 264" of the second ratio. In contrast, in Embodiment 2, the first ratio was defined using "the area of ​​the emission surface 263c of the first lens 263" as a specific example of the "relative size of the first lens 263" of the first ratio, and the second ratio was defined using "the area of ​​the emission surface 264c of the second lens 264" as a specific example of the "relative size of the second lens 264" of the second ratio.

[0099] Therefore, in Embodiment 2, the first ratio is the ratio of the area of ​​the emission surface 263c of the first lens 263 (more specifically, the vertical size of the emission surface 263c) to the light-emitting area H10 of the first light-emitting element 21c (more specifically, the vertical size of the light-emitting area H10). The second ratio is the ratio of the area of ​​the emission surface 264c of the second lens 264 (more specifically, the vertical size of the emission surface 264c) to the light-emitting area H11 of the second light-emitting element 21d (more specifically, the vertical size of the light-emitting area H11).

[0100] Thus, even when the first and second ratios are defined in this way, as in the first embodiment, by making the first ratio larger, it is possible to give the light distribution characteristic Q10 of the light emitted from the first lens 263 a steeper cut-off line. Similarly, by making the second ratio smaller, it is possible to prevent the light distribution characteristic Q11 of the light emitted from the second lens 264 from having a steep cut-off line.

[0101] Embodiment 2 is configured similarly to Embodiment 1, except that the definitions of the first and second ratios differ as described above.

[0102] Therefore, in Embodiment 2, as in Embodiment 1, the first ratio is greater than the second ratio, and the light-emitting area H10 of the first light-emitting element 21c (more specifically, the vertical size of the light-emitting area H10) is smaller than the light-emitting area H11 of the second light-emitting element 21d (more specifically, the vertical size of the light-emitting area H11) (Configuration 2). With this Configuration 2, as in Embodiment 1, the light distribution characteristics of the first lens 263 become light distribution characteristics that constitute the portion of the light distribution characteristics above the first maximum brightness direction of the light distribution characteristics of the illumination device 1 (i.e., the light distribution direction in which the brightness is at its maximum brightness in the light distribution characteristics of the illumination light of the illumination device 1), and have a sharp cut-off line KL1 above the first maximum brightness direction of the illumination light (for example, 15 degrees upward). Furthermore, with the above configuration 2, similar to embodiment 1, the light distribution characteristics of the second lens become light distribution characteristics that constitute the portion of the light distribution characteristics of the lighting device 1 that is below the first maximum brightness direction, and have a light distribution characteristic that does not have a cut line steeper than the cut line KL1.

[0103] (2) Effects As described above, the lighting device 1 according to Embodiment 2 comprises a plurality of light-emitting elements 21a and a plurality of lenses 261. The plurality of light-emitting elements 21a are arranged on the main surface of the circuit board 21b (substrate). The plurality of lenses 261 correspond to the plurality of light-emitting elements 21a. Each of the plurality of lenses 261 has an incident surface 263a, 264a, an exit surface 263c, 264c, and a reflecting surface 263b, 264b. The incident surfaces 263a, 264a are concave. The incident surfaces 263a, 264a face the corresponding light-emitting elements 21a. The reflecting surfaces 263b, 264b connect the ends of the incident surfaces 263a, 264a and the ends of the exit surfaces 263c, 264c. The plurality of light-emitting elements 21a include a first light-emitting element 21c and a second light-emitting element 21d. The first light-emitting element 21c has a first optical axis G1c. The second light-emitting element 21d has a second optical axis G1d. The plurality of lenses 261 include a first lens 263 and a second lens 264. The first lens 263 corresponds to the first light-emitting element 21c and emits light upward from a first brightness maximum direction, which is the light distribution direction in which the brightness of the combined light emitted from each of the plurality of lenses 261 is maximized. The second lens 264 corresponds to the second light-emitting element 21d and emits light downward from the first brightness maximum direction. The first ratio is greater than the second ratio. The first ratio is the ratio of the area of ​​the first emission surface 263c of the first lens 263 to the first light-emitting area H10 of the first light-emitting element 21c. The second ratio is the ratio of the area of ​​the second emission surface 264c of the second lens 264 to the second light-emitting area H11 of the second light-emitting element 21d. The first light-emitting area H10 of the first light-emitting element 21c is smaller than the second light-emitting area H11 of the second light-emitting element 21d.

[0104] In this configuration, the first ratio is greater than the second ratio, and the first light-emitting area H10 of the first light-emitting element 21c is smaller than the second light-emitting area H11 of the second light-emitting element 21d (configuration 2). With configuration 2, a steep cut-off line KL1 can be set on the upper side of the first maximum brightness direction of the combined light (illumination light) of the combined light emitted from each of the multiple lenses 261. Furthermore, with configuration 2, the multiple lenses 261 can be housed within the area of ​​the main surface of the circuit board 21b (substrate area), thereby ensuring the luminous flux required for illumination. Thus, it is possible to set a steep cut-off line KL1 on the upper side of the first maximum brightness direction of the illumination light while ensuring the luminous flux required for illumination with a limited substrate area.

[0105] (3) Variant The following describes a modified example of Embodiment 2.

[0106] (Variation 1) Referring to Figures 17 and 18, a modified example of Embodiment 2, specifically the lighting device 1, will be described.

[0107] In the modified example 1, the only difference from embodiment 2 is that the first ratio is 1.2 times or more the second ratio.

[0108] In typical lighting fixtures, the central luminance of the light source is 5000 cd / klm, and the speed of light is 50 klm.

[0109] If the first ratio is 1.2 times or more than the second ratio, then when lighting device 1 is a typical lighting fixture (i.e., the central luminance of lighting device 1 is 5000 cd / klm), the luminance above 15 degrees above the direction of maximum luminance of the lighting light from lighting device 1 (the first direction of maximum luminance) can be attenuated to 2500 cd. The above "2500 cd" is the luminance before the dimming time specified in area E1 of the light pollution countermeasures guidelines established by the Ministry of the Environment.

[0110] If we consider the light emitted from the second lens 264 as the illumination light from a typical lighting fixture, the light emitted from the second lens 264 has a central brightness of 5000 cd / klm and a luminous flux of 50 klm.

[0111] Figure 17 shows the light distribution of the illumination device (hereinafter referred to as "reference device") when the ratio of the area of ​​the lens's emission surface to the light-emitting area of ​​the light-emitting element is changed, using the lens shown in Figure 9 (i.e., a lens with a shape symmetrical in the vertical direction with respect to the optical axis of the corresponding light-emitting element). Graphs g1 to g7 in Figure 17 show the light distribution when the above ratio is "278", "204", "156", "123", "100", "83", and "69", respectively.

[0112] From Figure 17, we can obtain the graph Y1 shown in Figure 18. Graph Y1 in Figure 18 is a graph showing the correlation between the above ratio (= (area of ​​the lens emission surface) / (luminescent area of ​​the light-emitting element)) and the luminance in the light distribution direction 15 degrees above the direction of maximum luminance in the illumination light of the above reference device (hereinafter simply referred to as "luminance in the light distribution direction 15 degrees above"). In Figure 18, the horizontal axis is the value of the above ratio, and the vertical axis is the value of the luminance in the light distribution direction 15 degrees above. As shown in Figure 18, the luminance in the light distribution direction 15 degrees above is inversely proportional to the above ratio.

[0113] In typical lighting fixtures, the surface area of ​​the lens's emission surface is 600 mm². 2 The light-emitting area of ​​the light-emitting element is 7 mm². 2 Therefore, the above ratio for typical lighting fixtures is 600mm. 2 / 7mm 2= 86. Assuming that the ratio of the area of ​​the emission surface 264c of the second lens 264 to the emission area H11 of the second light-emitting element 21d (second ratio) is the same as the above ratio (=86) for a typical lighting device, the second ratio is 86. In this case, if the first ratio is greater than 1.2 times the second ratio (=86), the first ratio will be 103 (≒1.2 × 86) or greater. From Figure 18, when the horizontal axis is 103, the luminance in the light distribution direction of the upper 15 degrees is 50 cd / klm or less. Thus, when the first ratio is 1.2 times or more the second ratio, the luminance in the light distribution direction of the upper 15 degrees of the light distribution characteristics of the emitted light of the first lens 263 will be 50 cd / klm or less. Therefore, the luminance of the illumination light from lighting device 1 in the 15-degree upward direction is attenuated to 50 cd / klm (corresponding to the luminance of 2500 cd before the dimming time specified in area E1 above).

[0114] Based on the above, in the lighting device 1 according to Modification 1, the first ratio is 1.2 times or more the second ratio. With this configuration, a steep cut-off line KL1 can be set in the light distribution direction 15 degrees above the first maximum brightness direction of the illumination light (i.e., the composite light of the emitted light from each of the multiple lenses 261).

[0115] (Other variations) Modifications 1 to 3 of Embodiment 1 can also be applied to Embodiment 2.

[0116] (summary) The illumination device (1) according to the first embodiment comprises a plurality of light-emitting elements (21a) and a plurality of lenses (261). The plurality of light-emitting elements (21a) are arranged on the main surface of the substrate (21b). The plurality of lenses (261) correspond to the plurality of light-emitting elements (21a). Each of the plurality of lenses (261) has an incident surface (263a, 264a), an exit surface (263c, 264c), and a reflecting surface (263b, 264b). The incident surfaces (263a, 264a) are concave. The incident surfaces (263a, 264a) face the corresponding light-emitting elements (21a). The reflecting surfaces (263b, 264b) connect the ends of the incident surfaces (263a, 264a) and the ends of the exit surfaces (263c, 264c). The plurality of light-emitting elements (21a) include a first light-emitting element (21c) and a second light-emitting element (21d). The first light-emitting element (21c) has a first optical axis (G1c). The second light-emitting element (21d) has a second optical axis (G1d). The plurality of lenses (261) include a first lens (263) and a second lens (264). The first lens (263) corresponds to the first light-emitting element (21c) and emits light upward from a first maximum brightness direction, which is the light distribution direction in which the brightness of the combined light emitted from each of the plurality of lenses (261) is maximized. The second lens (264) corresponds to the second light-emitting element (21d) and emits light downward from the first maximum brightness direction. The first ratio is greater than the second ratio. The first ratio is the ratio of the height (L10) in the direction of the first optical axis (G1c) of the first lens (263) to the first light-emitting area (H10) of the first light-emitting element (21c). The second ratio is the ratio of the height (L11) in the direction of the second optical axis (G1d) of the second lens (264) to the second light-emitting area (H11) of the second light-emitting element (21d). The first light-emitting area (H10) of the first light-emitting element (21c) is smaller than the second light-emitting area (H11) of the second light-emitting element (21d).

[0117] In this configuration, the first ratio is greater than the second ratio, and the first light-emitting area (H10) of the first light-emitting element (21c) is smaller than the second light-emitting area (H11) of the second light-emitting element (21d) (Configuration 1). With Configuration 1, a steep cut-off line (KL1) can be set on the upper side of the first maximum brightness direction of the combined light (illumination light) of the combined light emitted from each of the multiple lenses (261). Furthermore, with Configuration 1, the multiple lenses (261) can be housed within the area of ​​the main surface of the substrate (21b) (substrate area), thereby ensuring the luminous flux required for illumination. Thus, it is possible to ensure the luminous flux required for illumination with a limited substrate area while setting a steep cut-off line (KL1) on the upper side of the first maximum brightness direction of the illumination light.

[0118] The illumination device (1) according to the second embodiment comprises a plurality of light-emitting elements (21a) and a plurality of lenses (261). The plurality of light-emitting elements (21a) are arranged on the main surface of the substrate (21b). The plurality of lenses (261) correspond to the plurality of light-emitting elements (21a). Each of the plurality of lenses (261) has an incident surface (263a, 264a), an exit surface (263c, 264c), and a reflecting surface (263b, 264b). The incident surfaces (263a, 264a) are concave. The incident surfaces (263a, 264a) face the corresponding light-emitting elements (21a). The reflecting surfaces (263b, 264b) connect the ends of the incident surfaces (263a, 264a) and the ends of the exit surfaces (263c, 264c). The plurality of light-emitting elements (21a) include a first light-emitting element (21c) and a second light-emitting element (21d). The first light-emitting element (21c) has a first optical axis (G1c). The second light-emitting element (21d) has a second optical axis (G1d). The plurality of lenses (261) include a first lens (263) and a second lens (264). The first lens (263) corresponds to the first light-emitting element (21c) and emits light upward from a first maximum brightness direction, which is the light distribution direction in which the brightness of the combined light emitted from each of the plurality of lenses (261) is maximized. The second lens (264) corresponds to the second light-emitting element (21d) and emits light downward from the first maximum brightness direction. The first ratio is greater than the second ratio. The first ratio is the ratio of the area of ​​the first emission surface (263c) of the first lens (263) to the first light-emitting area (H10) of the first light-emitting element (21c). The second ratio is the ratio of the area of ​​the second emission surface (264c) of the second lens (264) to the second light-emitting area (H11) of the second light-emitting element (21d). The first light-emitting area (H10) of the first light-emitting element (21c) is smaller than the second light-emitting area (H11) of the second light-emitting element (21d).

[0119] In this configuration, the first ratio is greater than the second ratio, and the first light-emitting area (H10) of the first light-emitting element (21c) is smaller than the second light-emitting area (H11) of the second light-emitting element (21d) (Configuration 2). With Configuration 2, a steep cut-off line (KL1) can be set on the upper side of the first maximum brightness direction of the combined light (illumination light) of the combined light emitted from each of the multiple lenses (261). Furthermore, with Configuration 2, the multiple lenses (261) can be housed within the area of ​​the main surface of the substrate (21b) (substrate area), thereby ensuring the luminous flux required for illumination. Thus, it is possible to ensure the luminous flux required for illumination with a limited substrate area while setting a steep cut-off line (KL1) on the upper side of the first maximum brightness direction of the illumination light.

[0120] In the lighting device (1) according to the third embodiment, in the second embodiment, the first ratio is 1.2 times or more the second ratio.

[0121] With this configuration, a steep cut-off line (KL1) can be set in the light distribution direction 15 degrees above the first maximum brightness direction of the illumination light (i.e., the composite light of the emitted light from each of the multiple lenses (261)).

[0122] The illumination device (1) according to the fourth embodiment further comprises a cover (3) in any one of the first to third embodiments. The cover (3) covers a plurality of light-emitting elements (21a) and a plurality of lenses (261). The ends of each of the plurality of lenses (261) on the side of the emission surface (263c, 264c) are integrally formed with the front wall portion (31f) of the cover (3).

[0123] This configuration allows multiple lenses (261) and a cover (3) to be integrally formed. As a result, the number of parts in the lighting device (1) can be reduced, and the lighting device (1) can be made thinner.

[0124] In the illumination device (1) according to the fifth embodiment, in any one of the first to fourth embodiments, the plurality of light-emitting elements (21a) further include a third light-emitting element having a third optical axis. The plurality of lenses (261) further include a third lens. The third lens corresponds to the third light-emitting element and emits light downward from the first maximum brightness direction. The third maximum brightness direction (θ3) in which the brightness of the light emitted from the third lens is maximum is directed downward from the second maximum brightness direction (θ2) in which the brightness of the light emitted from the second lens (264) is maximum. The maximum brightness (M21) of the third lens in the third maximum brightness direction (θ3) is smaller than the maximum brightness (M20) of the second lens (264) in the second maximum brightness direction (θ2).

[0125] This configuration allows for easy adjustment of the light distribution characteristics below the first maximum brightness direction in the combined light (illumination light) of the emitted light from each of the multiple lenses.

[0126] In the lighting device (1) according to the sixth embodiment, in any one of the first to fifth embodiments, the light distribution characteristics (Q0) of the composite light have a cut-off line (KL1) in the light distribution direction 15 degrees above the first maximum brightness direction.

[0127] With this configuration, it is possible to restrict the emission of illumination light (i.e., illumination light) from the combined light emitted from each of the multiple lenses (261) to a direction above the light distribution direction that is 15 degrees above the first direction of maximum brightness. [Explanation of Symbols]

[0128] 1. Lighting device 3 Cover 21a Light-emitting element 21c First light-emitting element 21d Second light-emitting element 21c First light-emitting element 21d Second light-emitting element 31f Front wall 261 Lens 263 First Lens 264 Second lens 21b Circuit board 263a,264a Incidence plane 263b,264b Reflective surface 263c Output surface (first exit surface) 264c Output surface (second exit surface) H10 Luminous area (first luminous area) H11 Luminous area (second luminous area) L10, L11 Height G1 optical axis G1c 1st optical axis G1d 2nd optical axis M20 Maximum Brightness (Second Maximum Brightness) M21 Maximum Brightness (Third Maximum Brightness) Q0 Light Distribution Characteristics θ2 Second direction of maximum brightness θ3 Third direction of maximum brightness

Claims

1. Multiple light-emitting elements arranged on the main surface of the substrate, The system comprises a plurality of lenses corresponding to the plurality of light-emitting elements, Each of the aforementioned plurality of lenses is A concave incident surface facing the corresponding light-emitting element, The exit surface and, It has a reflective surface that connects the end of the incident surface and the end of the exit surface, The plurality of light-emitting elements are A first light-emitting element having a first optical axis, A second light-emitting element having a second optical axis, The aforementioned multiple lenses are, A first lens corresponding to the first light-emitting element emits light upward from a first brightness maximum direction, which is the light distribution direction in which the brightness of the combined light emitted from each of the plurality of lenses is maximized, The device includes a second lens corresponding to the second light-emitting element, which emits light downward from the first direction of maximum brightness, The first ratio of the height in the direction of the first optical axis of the first lens to the first light-emitting area of ​​the first light-emitting element is greater than the second ratio of the height in the direction of the second optical axis of the second lens to the second light-emitting area of ​​the second light-emitting element. The first light-emitting area of ​​the first light-emitting element is smaller than the second light-emitting area of ​​the second light-emitting element. Lighting device.

2. Multiple light-emitting elements arranged on a substrate, The system comprises a plurality of lenses corresponding to the plurality of light-emitting elements, Each of the aforementioned plurality of lenses is A concave incident surface facing the corresponding light-emitting element, The exit surface and, It has a reflective surface that connects the end of the incident surface and the end of the exit surface, The plurality of light-emitting elements are A first light-emitting element having a first optical axis, A second light-emitting element having a second optical axis, The aforementioned multiple lenses are, A first lens corresponding to the first light-emitting element emits light upward from a first brightness maximum direction, which is the light distribution direction in which the brightness of the combined light emitted from each of the plurality of lenses is maximized, The device includes a second lens corresponding to the second light-emitting element, which emits light downward from the first direction of maximum brightness, The first ratio of the area of ​​the first emission surface of the first lens to the first light-emitting area of ​​the first light-emitting element is greater than the second ratio of the area of ​​the second emission surface of the second lens to the second light-emitting area of ​​the second light-emitting element. The first light-emitting area of ​​the first light-emitting element is smaller than the second light-emitting area of ​​the second light-emitting element. Lighting device.

3. The first ratio is 1.2 times or more the second ratio. The lighting device according to claim 2.

4. The system further comprises a cover that covers the plurality of light-emitting elements and the plurality of lenses. The end of each of the plurality of lenses on the side of the emission surface is formed integrally with the front wall portion of the cover. A lighting device according to any one of claims 1 to 3.

5. The plurality of light-emitting elements further include a third light-emitting element having a third optical axis, The plurality of lenses further include a third lens corresponding to the third light-emitting element, which emits light downward from the first maximum brightness direction, The third direction of maximum brightness, where the brightness of the light emitted from the third lens is maximized, is directed downwards from the second direction of maximum brightness, where the brightness of the light emitted from the second lens is maximized. The maximum brightness of the third lens in the third maximum brightness direction is smaller than the maximum brightness of the second lens in the second maximum brightness direction. A lighting device according to any one of claims 1 to 3.

6. The light distribution characteristics of the composite light have a cut-off line in the light distribution direction 15 degrees above the first direction of maximum brightness. A lighting device according to any one of claims 1 to 3.

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