lighting equipment

Abstract

To achieve a small-sized lighting device while maintaining a relatively narrow radiation angle.SOLUTION: A lighting device 300 includes: a light source 320 which emits light in an optical axis 325 direction; and a plurality of reflecting plates 331. The light source 320 has a prescribed light emitting region LES. Each of the plurality of reflecting plates 331 has a first reflecting plate M1 which surrounds an optical axis 325 and has a reflecting surface between an upper opening which connects an upper end M1u and a lower opening which connects a lower end M1d, and a second reflecting plate M2 which surrounds the optical axis 325 inside the first reflecting plate M1 and has a reflecting surface between an upper opening which connects an upper end M2u and a lower opening which connects a lower end M2d. Of a light beam c1 directing toward the first reflecting plate M1 from an end of the light emitting region LES, there is a light beam d1 which strikes a rear face of the second reflecting plate M2 after being reflected on the first reflecting plate M1.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a lighting device that can be made compact, and in particular to a lighting device that can emit light at narrow or medium angles and has little color unevenness even when using LEDs with different light emission colors. [Background technology]

[0002] In lighting devices such as spotlights that are primarily used to illuminate objects, narrowing the radiation angle has been problematic in that the lighting device becomes larger. For example, Patent Document 1 describes a comparative lighting device that uses only a reflector, and an example in which a lens is provided near the light source in addition to the reflector to avoid the device becoming larger, and states that "in the LED lighting device of this embodiment, it is possible to increase the amount of light that reaches the inner surface 3a of the reflector 3 while reducing the height of the reflector 3 compared to the LED lighting device of Comparative Example 1."

[0003] Cited Document 2 describes a lighting device using multiple reflectors. It shows a structure including an LED chip, a small-diameter reflector positioned in front of the LED chip to receive light from the LED chip and project it forward, and a reflector surrounding the LED chip and the small-diameter reflector from the outside to reflect the light from the LED chip forward.

[0004] A common method of adjusting color is to use two white light sources with a high color temperature and a low color temperature, or three or more color light sources, and change the brightness ratio between them, but using LEDs of multiple colors can result in color unevenness. Cited document 3 describes a lighting device that uses an LED group consisting of red, green, blue, and white LEDs, and has a section that narrows the light emitted by the LED group, promoting the mixing of light in front of the narrowing and suppressing color unevenness. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-127896 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-181100 [Patent Document 3] Japanese Patent Application Publication No. 2017-033724 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to realize a compact lighting device while maintaining a relatively narrow radiation angle, such as a narrow angle or a medium angle. Another object of the present invention is to suppress color unevenness in lighting devices such as spotlights and downlights that have LEDs of multiple colors arranged in the light-emitting area. [Means for solving the problem]

[0007] The present invention provides an illumination device including a light source that irradiates light in an optical axis direction and a plurality of reflectors, the light source has a predetermined light-emitting area; The plurality of reflectors include a first reflector having a reflecting surface between an upper opening that surrounds the optical axis and connects the upper ends and a lower opening that connects the lower ends, and a second reflector having a reflecting surface between an upper opening that surrounds the optical axis and connects the upper ends and a lower opening that connects the lower ends, inside the first reflector. a third reflector that surrounds the optical axis inside the second reflector and has a reflecting surface between an upper opening connecting the upper ends and a lower opening connecting the lower ends; Equipped with Among the light rays traveling from the end of the light emitting region toward the first reflector, there are light rays that are reflected by the first reflector and then strike the rear surface of the second reflector. the law of nature , a light ray traveling from an end of the light emitting region toward the second reflector is incident on the inside of the second reflector, The light beam traveling from the end of the light emitting region toward the third reflector is incident on the rear surface of the third reflector. It is a lighting device. [Effects of the Invention]

[0008] According to the present invention, in a light source using LEDs of a plurality of emitted colors and an illumination device using the light source, it is possible to reduce the size of the illumination device while maintaining a relatively narrow radiation angle. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view of a lighting device according to a first embodiment; [Figure 2] 1 is a cross-sectional view of a main part of an illumination device according to a first embodiment. [Figure 3] An example in which the control device and lighting device of embodiment 1 illuminate a wall surface [Figure 4] In the first embodiment, the trajectory of the light ray emitted from the center of the light source and reflected by the upper ends of the reflectors M1, M2, M3, and M4 [Figure 5] In the first embodiment, the trajectory of the light ray emitted from the center of the light source and reflected by the lower ends of the reflectors M1, M2, M3, and M4 [Figure 6] In the first embodiment, the trajectories of light rays emitted from the edge of the light-emitting area LES and reflected by the upper ends of the reflectors M1, M2, M3, and M4 [Figure 7] In the first embodiment, the trajectories of light rays emitted from the edge of the light-emitting area LES and reflected by the lower ends of the reflectors M1, M2, M3, and M4 [Figure 8] An explanatory diagram of reflectors M1, M2, M3, and M4 cut on a plane including the optical axis [Figure 9] Dependence of efficiency on shielding angle in embodiment 1 [Figure 10] Dependence of axial luminous intensity on shielding angle in embodiment 1 [Figure 11] FIG. 10 is a plan view of a light source 320B used in the second embodiment. [Figure 12] Chromaticity diagram for explaining the chromaticity of LEDs [Figure 13] FIG. 10 is a plan view of a light source 420 used in the second embodiment. [Figure 14] Relationship between LES and 1 / 2 illuminance angle in embodiment 2 (actual measurement) and embodiment 1 (simulation) [Figure 15] 10 is an explanatory diagram of a lighting device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] <Terminology> The terms 1 / 2 illuminance angle and 1 / 2 beam angle are used to describe the radiation angle, which is the spread of light distribution. 1 / 2 illuminance angle refers to the angle between the optical axis of a lighting fixture and a line drawn on a plane perpendicular to the lighting fixture's optical axis, connecting the position where the illuminance is 1 / 2 of the center and the lighting source of the lighting fixture. 1 / 2 beam angle refers to the direction where the luminous intensity is 1 / 2 of the luminous intensity in the central axis direction. In this specification, luminous intensity distribution angle will mainly be expressed as 1 / 2 illuminance angle.

[0011] In this specification, the narrow angle means a half illumination angle of 15 degrees or less, and the medium angle means 15 degrees or more and 25 degrees or less, and both together constitute a relatively narrow radiation angle.

[0012] <Embodiment 1> <Basic configuration> FIG. 1 shows a perspective view of an illumination device 300 according to this embodiment. The illumination device 300 is a large spotlight primarily intended for outdoor use, and includes an optical system housing 330, a reflector group 331 consisting of four reflectors (and a hood 332, described later), three reflector support plates 335, an exit window 340, a heat sink 350, a power supply housing 360, an angle adjustment unit 365, and a fixing unit 370. For illustrative purposes, an optical axis 325 extending from the center of the light source 320 toward the light emission direction is shown. The illumination device 300 is intended for use, for example, with the fixing unit 370 attached to a wall surface, emitting light either downward or upward.

[0013] 2 shows a cross-sectional view of the main part of the lighting device 300 taken along the optical axis 325. The light source 320 has a circular light-emitting surface (LES) with a diameter of φ (phi). The light source 320 is fixed to the heat sink 350 by a light source holder 322. The light emitted from the light source 320 has an approximately Lambertian angular dependence of relative luminous intensity (cosθ, where θ is the angle from the optical axis) centered on the optical axis 325.

[0014] The optical system housing section 330 houses a group of reflectors 331 consisting of four reflectors surrounding the optical axis and four hoods 332 connected to them (eight are shown as this is a cross-sectional view). Both sides of the hood 332 are painted black to filter out unwanted light. An exit window 340 is provided on the front side. The exit window 340 serves to prevent water from entering the interior. A transparent plate may be used as the exit window 340, but a light-diffusing plate may also be used to prevent color unevenness, as described below. A power supply 361 is housed in the power supply housing 360, and a wireless module 367 is connected to the power supply 361.

[0015] <Reflector configuration> The reflector group 331 includes a first reflector M1, a second reflector M2, a third reflector M3, and a fourth reflector M4, arranged from the side farther from the optical axis (outside) toward the side closer to the optical axis (inside). Each reflector has a shape similar to a paraboloid of revolution with the center of the light-emitting area LES of the light source 320 as its focal point, and a reflective surface is provided between an upper opening connecting the upper ends and a lower opening connecting the lower ends. However, to reduce color and brightness unevenness, the paraboloid of revolution may be deviated from the paraboloid of revolution by adding a diffusing shape such as a textured or streaked shape (described below). Furthermore, color unevenness can also be reduced by slightly deviating the rotational symmetry axes of some reflectors from the optical axis, rather than aligning the rotational symmetry axes of all reflectors with the optical axis.

[0016] <Control and wall illumination> FIG. 3 shows an example in which a control device 380 for a lighting device 300 and emitted light 326 from the lighting device 300 attached to a wall surface 390 illuminate an illumination area 391 on the wall surface 390.

[0017] Illumination device 300 has a built-in power supply 361, which has three channels of drive output for independently driving three color LEDs, and is controlled by a control signal carried by radio waves 385 transmitted from control device 380. Control device 380 is a smartphone, tablet, or PC with lighting control software installed, and the control signal is transmitted wirelessly to wireless module 367, which is a receiving device. Wireless module 367 is connected to a slot provided in power supply 361, and by transmitting a lighting control signal to power supply 361, the three channels of drive output of power supply 361 are each controlled.

[0018] It should be noted that lighting control is often performed via a repeater called a gateway, a server, or a cloud, rather than direct communication between the control device 380 and the lighting device 300. Wired control may also be used instead of wireless control.

[0019] <Light trajectory> Figure 4 shows four reflectors M1, M2, M3, and M4, the light-emitting area LES (x = -20 to 20 mm range), and the trajectories of light rays a1, a2, a3, and a4 emitted from the center of the light source. The hoods 332 connected to the upper ends of each reflector are not shown. x is the radial distance from the center of the light source (unit: mm), y is the distance from the center of the light source in the optical axis direction (unit: mm), and the optical axis overlaps with the y axis.

[0020] The surfaces of the four reflectors on the optical axis side are called the front surfaces, and the surfaces opposite the optical axis side are called the back surfaces.

[0021] The upper ends M1u, M2u, M3u, and M4u of the four reflectors are all at a distance L of 55 mm from the plane of y=0 that passes through the center of the light source.

[0022] The lower end M2d of the second reflector M2 is located on the line connecting the center of the light source and the upper end M1u of the first reflector M1, and the light ray a1 is reflected by the upper end M1u of the first reflector M1 and emitted as the light ray b1. Therefore, all of the light emitted from the center of the light source at an angle between the y-axis and the direction of the light ray a1 is reflected in the y-axis direction by the first reflector M1.

[0023] The lower end M3d of the third reflector M3 is located on the line connecting the center of the light source and the upper end M2u of the second reflector M2, and the light ray a2 is reflected by the upper end M2u of the second reflector M2 and emitted as the light ray b2. Therefore, all of the light emitted at an angle between the directions of the light ray a1 and the light ray a2 is reflected in the y-axis direction by the second reflector M2.

[0024] The lower end M4d of the fourth reflector M4 is located on the line connecting the center of the light source and the upper end M3u of the third reflector M3, and the light ray a3 is reflected by the upper end M3u of the third reflector M3 and emitted as the light ray b3. Therefore, all of the light emitted at an angle between the directions of the light ray a2 and the light ray a3 is reflected in the y-axis direction by the second reflector M2.

[0025] Note that "on the line" does not refer to a single geometric point, but also includes cases where the bottom end is intentionally placed slightly below the line to ensure that it is on the line even if there is a manufacturing error, or cases where the bottom end is placed slightly above the line due to a manufacturing error, as long as the effects of the present invention are achieved.

[0026] Light ray a4 is reflected by the upper end M4u of the fourth reflector M4 and emitted as light ray b4. Therefore, all light emitted at an angle between the direction of light ray a3 and the direction of light ray a4 is reflected in the y-axis direction by the second reflector M2. On the other hand, light emitted at an angle between the direction of light ray a4 and the optical axis direction is emitted to the outside as is.

[0027] FIG. 5 shows the loci of light rays c1, c1K, c2, c3, and c4 (light rays emitted from the light source) emitted from the center of the light source toward the lower end of each reflector.

[0028] Light rays c1, c2, c3, and c4, represented by dotted lines, are reflected by the lower ends M1d, M2d, M3d, and M4d of the reflectors, respectively, to become light rays d1, d2, d3, and d4 (reflected light rays). However, light ray d1, represented by a thick dotted line, is blocked by the second reflector M2. While this type of design is not generally used, here light ray d1 is intentionally blocked by the second reflector M2 (for example, in Figure 3 of Patent Document 2, light emitted directly to the side and reflected by the "reflector" is not blocked by the "small diameter reflector").

[0029] The light ray c1K represented by the dotted line is emitted at an angle of shading angle θ=7.5° with respect to the x-axis direction, is reflected by the first reflector M1 to become a light ray parallel to the optical axis, and becomes light ray d1K that is emitted to the outside just outside the upper end M2d of the second reflector M2.

[0030] That is, the upper end of the second reflector M2 is set at an obscuration angle θ of 7.5°, which is the angle between the x-axis and the light ray c1K emitted from the light source, so that the light ray c1K emitted from the light source is reflected by the first reflector M1 and becomes a light ray d1K that travels parallel to the optical axis, and the reflected light ray d1K can pass just outside the upper end of the second reflector M2. The x-axis is in a plane perpendicular to the optical axis.

[0031] The reason for providing a non-zero shading angle is that by providing a shading angle, reflectors M2, M3, and M4 are positioned on the outside (close to first reflector M1), reducing the impact of "light on the back surface of the reflectors," as described below, and leading to improved axial luminous intensity. On the other hand, while the utilization efficiency of light directed in a direction close to horizontal decreases, because light source 320 has a Lambertian light distribution characteristic (cosθ, where θ is the angle from the optical axis), the luminous intensity of light ray c1 directed in a direction close to 90°, even at a 7.5° angle, is only about 13% of the luminous intensity of light directed in the direction of the optical axis. Therefore, by setting the shading angle to an appropriate value, it is possible to reduce light loss due to not using light directed in a direction less than the shading angle. The impact of a shading angle other than 0° on the efficiency and axial luminous intensity of lighting device 300 will be described later.

[0032] The upper end of the third reflector M3 is positioned so that ray c2 emitted from the center of the light source is reflected at the lower end of the second reflector M2 to become ray d2 that travels parallel to the optical axis, and the reflected ray d2 can pass just outside the upper end of the third reflector M3.

[0033] The upper end of the fourth reflector M4 is positioned so that ray c3 emitted from the center of the light source is reflected at the lower end of the third reflector M3 and becomes ray d3 that travels parallel to the optical axis, and the reflected ray d3 can pass just outside the upper end of the fourth reflector M4.

[0034] By setting it in this way, the light beam emitted from the center of the light source is reflected by one of the reflectors, and a relatively narrow radiation angle such as a narrow angle or a medium angle can be maintained. FIG. 6 shows the trajectories of light rays a1, a2, a3, and a4 emitted from the edge of the light-emitting area LES (20 mm from the center of the light source) toward the upper end of each reflector.

[0035] Light rays a1 and a2 (shown by thin dotted lines) heading toward the upper ends M1u and M2u of the reflectors are reflected by the upper ends M1u and M2u of the reflectors, respectively, and emerge as light rays b1 and b2.

[0036] On the other hand, light rays a3 and a4 (shown by thick dotted lines) heading toward the upper ends M3u and M4u of the reflectors strike the back surfaces of the reflectors M3 and M4, respectively, and become light rays b3 and b4 when reflected. This makes it difficult to control these light rays; however, the angle of the direction from the end of the light-emitting area LES that strikes the reflectors M3 and M4 is limited, and it is assumed that such light components are small. Therefore, the configuration is such that light rays a3 and a4 strike the back surfaces of the reflectors M3 and M4. The back surfaces of the reflectors M3 and M4 may be subjected to a low-reflectivity treatment to reduce reflectivity, such as black painting. The low-reflectivity treatment refers to a treatment that reduces reflectivity to 20% or less, preferably 10% or less. The back surfaces of the reflectors M3 and M4 may be mirror-finished to effectively utilize the light that strikes them.

[0037] By providing the shielding angle, the reflectors M2, M3, and M4 can be positioned on the outside closer to the first reflector M1, which reduces the solid angle (i.e., the proportion of light) from the edge of the light-emitting area LES to the back surfaces of the reflectors M3 and M4.

[0038] FIG. 7 shows the trajectories of light rays c1, c2, c3, and c4 emitted from the edge of the light-emitting area LES (20 mm from the center of the light source) toward the lower end of each reflector.

[0039] A light ray c1 (shown by a thin dotted line) heading toward the lower end M1d of the first reflector M1 is reflected by the first reflector M1 to become a light ray d1, but is blocked by the second reflector M2.

[0040] A ray c2 (shown by a thin dotted line) heading toward the lower end M2d of the second reflector M2 is reflected by the second reflector M2 and emerges as a ray d2.

[0041] Light rays c3 and c4 (shown by thick dotted lines) heading toward the lower ends M3d and M4d of reflectors M3 and M4 are reflected by the back surfaces of reflectors M3 and M4, respectively, and become light rays d3 and d4 after reflection. However, this effect is suppressed because the back surfaces of the reflectors are painted black.

[0042] <Countermeasures for uneven color of reflector> As shown in Fig. 8, which is an explanatory diagram of reflectors M1, M2, M3, and M4 cut by a plane including the optical axis, the reflective surface of each reflector has a textured pattern (multiple convex or concave portions) to prevent color unevenness. Each convex or concave portion is separated by, for example, a square or hexagon and arranged in a row, but may have any other polygonal shape.

[0043] In the first reflector M1, the grained protrusions (or recesses) are arranged in the direction of arrow S1, which is parallel to the arrow V1 indicating the direction of the cut surface. Meanwhile, in the second reflector M2, the grained protrusions (or recesses) are arranged in the direction of arrow S2, which is diagonally rightward relative to the arrow V2 indicating the direction of the cut surface. In the third reflector M3, the grained protrusions (or recesses) are arranged in the direction of arrow S3, which is diagonally leftward relative to the arrow V3 indicating the direction of the cut surface. In the fourth reflector M4, the grained protrusions (or recesses) are arranged in the direction of arrow S4, which is diagonally rightward relative to the arrow V4 indicating the direction of the cut surface. By varying the cut surface direction and the direction in which the protrusions (or recesses) are arranged for each reflector, color unevenness can be reduced. For example, the directions may be alternately changed between right and left for adjacent reflectors.

[0044] The direction of the series of grain patterns on the first reflecting plate M1 may be set to face leftward with respect to the arrow V1 (similar to the arrow S3).

[0045] <Characteristics> The portion of the lighting device 300 with the reflector designed as described above, which corresponds to the optical system housing 330, has the advantage of being approximately 40% smaller in height (from 160 to 65) and approximately 70% smaller in diameter (from 125 to 90) than a conventional lighting device with a single reflector. The optical characteristics were simulated using ray tracing. When a 1000 lm light source was used, the results were a 1 / 2 illuminance angle of 19°, a light extraction efficiency of 87.2%, and an axial luminous intensity of 4020 cd. The actual measurement data will be described in the explanation of the second embodiment.

[0046] <Shielding angle dependence> As a variation of embodiment 1, a ray tracing simulation was performed on the light extraction efficiency and optical axis intensity when the distance L was set to 55 mm and 80 mm and the shading angle was set to 0° to 20°. However, by changing the parameters, the radiation angle (1 / 2 illuminance angle) also changed slightly.

[0047] A graph showing the efficiency dependency on shield angle is shown in Figure 9. Black circles (●) represent the case where L = 55 mm, and white circles (○) represent the case where L = 80 mm. In both cases, it can be seen that by setting the shield angle between 3° and 20°, the efficiency is improved compared to when the shield angle is 0°.

[0048] A graph showing the dependence of axial luminous intensity on interception angle is shown in Figure 10. The black circles (●) represent the case where L = 55 mm. When L = 55 mm, it can be seen that by setting the interception angle between 3° and 10°, the axial luminous intensity is improved compared to when the interception angle is 0°.

[0049] <Embodiment 2> <Basic configuration> The lighting device 400 according to this embodiment is obtained by replacing the light source 320 in the lighting device 300 with light sources 420, 320B, 320C, and 320D having light emitting regions LES with diameters of 17, 37.4, 45.8, and 61.4 mm respectively, and measuring the characteristics. The optical system such as the reflector group 331 uses the same components as those in the first embodiment. However, a case using only the first reflector as a comparative example will also be described in this embodiment section.

[0050] <Light source> To explain the common structure of the light sources 320B, 320C, and 320D, a plan view of the light source 320B (diameter of the light emitting region LES = 37.4 mm) used in this embodiment is shown in FIG. 11. The light source 320 is formed by mixing 25 each of three-color SMD (Surface Mount Device type, surface-mounted type) LEDs 323A, 323B, and 323C in the light emitting region LES on a substrate 321 printed with a wiring pattern, and connecting them in series with the wiring inside the substrate (the number of LEDs is different for the light sources 320C and 320D). The light source 320B has a mounting hole 325, and is fastened to the heat sink 350 by passing a screw through the mounting hole 325. The light source 320B includes wiring terminals 326A (for LED 323A), wiring terminals 326B (for LED 323B), wiring terminals 326C (for LED 323C), and a wiring terminal 326E (common terminal), and is connected to a power supply 361 having three outputs, and the light emission of each LED is controlled.

[0051] In this case, the arrangement of the LEDs is a mixed arrangement such that the numbers of LEDs 323A, B, and C are the same and not biased. Also, for the convenience of wiring the same-color LEDs in series with the wiring inside the substrate 321, the same-color LEDs are arranged so as to be adjacent diagonally.

[0052] In the simulation in the first embodiment, it is assumed that there are light sources throughout the inside of the light emitting region LES. However, as shown in FIG. 11, since there is no space to arrange one LED near the outer periphery of the actual light emitting region LES, there is a portion where no LED is arranged.

[0053] <Chromaticity of LED> The LEDs 323A, 323B, and 323C used in this embodiment are either a red LED "R," a yellow-white LED "Yw," or a bluish-white LED "Bw." Note that Yw is a color close to yellow on a chromaticity diagram, but it also appears greenish-white. Figure 12 is a chromaticity diagram (CIE 1931 chromaticity coordinate diagram) for explaining the chromaticity of these LEDs, and for reference, dotted lines connect the chromaticities of blackbody radiation at each color temperature.

[0054] The red LED R emits light with a chromaticity in the range enclosed by the chromaticity boundary line E, which is (0.66, 0.23), (0.423, 0.355), and (0.5, 0.5) in the chromaticity coordinates of Figure 12. An example is (0.60, 0.38). Note that this is not the same as the general definition of red.

[0055] The yellow-white LED Yw emits light with a chromaticity in the range surrounded by (0.5, 0.5), (0.423, 0.355), (0.342, 0.312), (0.352, 0.44), (0.37, 0.63) and the chromaticity boundary line E in the chromaticity coordinates of FIG. 12, and one example is (0.44, 0.47).

[0056] The bluish white LED Bw emits light with a chromaticity in the range enclosed by (0.336, 0.24), (0.352, 0.44), (0.15, 0.2), and (0.2, 0.1) in the chromaticity coordinates of FIG. 12, and one example is (0.23, 0.26).

[0057] Within the chromaticity range of Yw, the distance d from the line connecting the chromaticity of blackbody radiation at each color temperature uv is preferably in the positive range, and d uv is particularly preferably from plus 0.03 to 0. Within the chromaticity range of Bw and R, the distance from the line connecting the chromaticity of blackbody radiation at each color temperature is d uv is particularly preferably in the range of plus 0.03 to minus 0.03.

[0058] Note that the chromaticity of each LED can also be expressed in terms of the chromaticity coordinates (u‘, v’) in CIE1976 instead of the chromaticity coordinates (x, y) in CIE1931, and the two can be mutually converted by the conversion formula u’ = 4x / (-2x + 12y + 3) and v’ = 9y / (-2x + 12y + 3). It may also be expressed in other chromaticity coordinate systems.

[0059] <LED Structure> The LEDs 323A, 323B, and 323C used in the embodiments include a package having a bottom surface and four side surfaces, with the terminals on the bottom surface or side surfaces connected to the wiring on the substrate, a blue LED chip made of InGaN, and a resin containing a phosphor. The blue LED chip is fixed to the bottom surface of the package, the electrodes of the blue LED chip are connected to the electrodes of the package by wires or the like, and the upper surface and side surfaces of the blue LED chip are covered with the phosphor-containing resin. The width of the LED package is, for example, about 4 mm square.

[0060] The LED 323B with the emission color Bw (hereinafter abbreviated as Bw) has the upper surface and side surfaces of the InGaN-based blue LED chip covered with a resin containing green phosphor particles or yellow phosphor. It may further contain red phosphor particles.

[0061] The LED 323C with the emission color Yw (hereinafter abbreviated as Yw) is the same as Bw in that an InGaN-based blue LED chip is arranged at the bottom of the package, and the upper surface and side surfaces of the InGaN-based blue LED chip are covered with a resin containing green phosphor particles or yellow phosphor, but the concentration of the phosphor is higher than that of Bw. It may further contain red phosphor particles.

[0062] Also, the LED 323A with the emission color R (hereinafter abbreviated as R) has the upper surface and side surfaces of the InGaN-based blue LED chip covered with a resin containing red phosphor particles.

[0063] Instead of an InGaN blue LED chip, an AlGaInP LED chip can be used for R, covered with a resin that does not contain phosphor. An LED package using an AlGaInP LED chip for R is preferable because it does not contain blue in the emission spectrum, but the driving voltage is different from that of Bw or Yw, making the driving circuit more complex. An LED package combining a blue LED chip and a red phosphor for R requires processing to reduce the blue in the emission spectrum. For example, it is preferable to increase the concentration of the red phosphor to reduce the proportion of light emitted from the blue LED chip to the outside, but a filter that absorbs blue can also be used.

[0064] In each of the above LEDs, the yellow phosphor particles are, for example, (Y 1-x Gd x )3AlO 12 :Ce 2+ (0≦x≦1), and for green phosphor particles, for example, Lu3Al5O 12 :Ce 2+ For example, Sr x Ca 1-x AlSiN3:Eu 3+ (0≦x≦1) Phosphor, Sr[LiAl3N4]:Eu 2+ and K2SiF6:Mn 4+ Phosphors can be preferably used, and quantum dots can also be preferably used.

[0065] <Light source 420> Light source 420 is a COB (Chip On Board) type, with approximately 1 mm square CSP (Chip Scale Package) LEDs 423A, 423B, and 423C arranged in a light-emitting area (LES) on the COB. A CSP LED consists of a blue LED chip made of InGaN and a resin containing phosphor that covers the top and sides of the blue LED chip. To reduce size, the CSP LED typically does not have a package that frames the resin on the sides. Electrodes are exposed from the bottom of the blue LED chip.

[0066] 13 is a plan view of light source 420. Twenty-four LEDs (423A, 423B, and 423C) of three colors are arranged in a light-emitting region LES on substrate 421, which is an aluminum plate on which an insulating film and wiring pattern are formed, in a mixed arrangement as shown in FIG. 13. The LEDs of each color are connected in series with wiring inside the substrate. Substrate 421 has mounting holes 425 through which screws are passed to fasten the substrate to a heat sink. Light source 420 has wiring terminals 426A (for LED 423A), 426B (for LED 423B), 426C (for LED 423C), and 426P (common terminal), and is connected to a power supply 461 with three outputs (the rated output of which differs from that of power supply 361), and the light emitted by each LED is dimmed and adjusted to the desired color.

[0067] The LEDs are arranged so that the number of LEDs 423A, 423B, and 423C is approximately equal and evenly spaced. The diameter of the light-emitting area LES is approximately 17 mm.

[0068] <1 / 2 illumination angle> The relationship between the light-emitting area LES and the 1 / 2 illuminance angle in this embodiment (actual measurement) and embodiment 1 (simulation) is shown in Figure 14. When the same reflector group 331 is used, as the light-emitting area LES increases, the light source changes from a point light source to a more diffuse light source, making it difficult to focus the light in the optical system and increasing the 1 / 2 illuminance angle. It can be seen that the simulation values ​​are almost on the line connecting the actual measurement values.

[0069] <Axis luminosity> Using light source 320D (light emitting area LES = 61.4 mm), we compared the axial luminous intensity (here, luminous intensity cd per 1000 (lm) of luminous flux) when the reflector group 331 consisting of four reflectors M1, M2, M3, and M4 was replaced with reflector 431, which consisted of only the first reflector M1.

[0070] When only the first reflector M1 was used, the half illuminance angle was 28° and the on-axis luminous intensity was 1316 cd (when the luminous flux of the light source was 1000 (lm)), whereas when the reflector group 331 was used, the half illuminance angle was 29° and the on-axis luminous intensity was 1544 cd (when the luminous flux of the light source was 1000 (lm)), an increase of 17% in the on-axis luminous intensity. This demonstrates through experiments that this reflector is effective in improving the on-axis luminous intensity.

[0071] <Embodiment 3> <Basic configuration> The lighting device 700 according to this embodiment is a spotlight that is primarily used indoors. In Fig. 15, which is an explanatory diagram illustrating only the cross section of the optical system housing 730, which is a key component, and side views of the other components, a power supply unit 760 of the lighting device 700 is fixed to a wiring duct 780 installed on the ceiling. By moving a lever 775, the power supply unit 760 can be attached to or detached from the wiring duct 780. An arm 770 is connected to the power supply unit 760 via a joint 765, and is rotatable about an axis pointing downward. The orientation of the lighting body, which is made up of the optical system housing 730 and the heat sink 750, can be changed by a joint 755.

[0072] In the optical system housing 730, the light source 720 is fixed to the heat sink 750 by a light source holder 722. The light emitted from the light source 720 has an approximately Lambertian (cos θ, where θ is the angle from the optical axis) angular dependence of the relative luminous intensity centered on the optical axis 725.

[0073] The optical system housing section 730 houses a reflector group 731 consisting of three reflectors (first reflector, second reflector, and third reflector) and three hoods 732 connected to them (six are shown because this is a cross-sectional view). Both sides of the hood 732 are painted black to filter out unnecessary light. An exit window 740 is provided in front of it. A transparent plate may be used as the exit window 740, but a light-diffusing plate may also be used to prevent color unevenness.

[0074] <Reflector configuration> The reflector group 731 is composed of three reflectors, a first reflector M1, a second reflector M2, and a third reflector M3, with the fourth reflector M4 omitted from the reflector group 331. The reflector group 731 is smaller in size than the reflector group 731 but has a similar shape, and the shading angle θ is 7.5°.

[0075] In this embodiment, the length of the optical system housing portion can be made shorter than that of conventional indoor spotlights, and therefore the light source can be suitably used as a small spotlight that does not create a feeling of oppression indoors.

[0076] <Notes and variations> (1) In this application, the term "LED" refers to an LED package or CSP-type LED that has an LED chip, which is a semiconductor chip, as a component and emits a single color, but it may also refer to just the LED chip, which is a semiconductor chip. While the entire light source or lighting device equipped with an LED is generally referred to as an LED, this is not the meaning of the term used in this application.

[0077] (2) Although the embodiment has been described in which the light source uses LEDs that emit light of three colors, the LEDs may be of one color or two colors.

[0078] (3) Although the three-color LEDs described above are red (R), yellow-white (Yw), and blue-white (Bw), other three-color LEDs including red may also be used. For example, R, Yw, and blue (B) LEDs (with chromaticity coordinates x≦0.2, y≦0.2) may be used. Three-color LEDs consisting of R, green (G) LEDs (with chromaticity coordinates x≦0.35, y≧0.4), and blue (B) may also be used. R, G, and B are all primary colors, but R is the most noticeable color. Furthermore, R, G, and B may be combined with white (e.g., a daylight white LED or a daylight LED).

[0079] (4) Although a spotlight is used as an example of the lighting device, a downlight or a universal (direction-variable) downlight may also be used.

[0080] (5) Although the example of wireless control has been given as a method for controlling the lighting device, wired control may also be used.

[0081] (6) The unit of luminous flux, lumen, is written in parentheses as (lm) to distinguish it from the confusingly similar letter l (el) and the number 1.

[0082] It should be noted that the above-described embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present invention should not be interpreted solely by the above-described embodiments, but should be defined by the claims. Furthermore, all modifications within the scope and meaning equivalent to the claims are included. [Explanation of symbols]

[0083] 300, 400, 700 lighting equipment 320, 420, 720 light source 321, 421 board 322, 722 Light Source Holder 323A, 323B, 323C, 423A, 423B, 423C LED 325, 725 optical axis 325, 425 mounting holes 326 Emitted Light 326A, 326B, 326C, 326E, 426A, 426B, 426C, 426P Wiring terminal 330, 730 Optical system housing 331, 731 Reflector group 332, 732 Food 335 Reflector support plate 340, 740 exit window 350, 750 heat sink 360 Power supply compartment 361, 461 power supply 365 Angle adjustment section 367 Wireless Module 370 Fixed part 380 Control Device 385 Radio Waves 390 Wall 391 Irradiation area 755 Joint 760 Power Supply Unit 765 Joint 770 Arm 775 Lever 780 Wiring Duct

Claims

[Claim 1] An illumination device comprising a light source that irradiates light in an optical axis direction and a plurality of reflectors, the light source has a predetermined light-emitting area; the plurality of reflectors include a first reflector having a reflecting surface between an upper opening that surrounds the optical axis and connects its upper ends and a lower opening that connects its lower ends; a second reflector having a reflecting surface inside the first reflector that surrounds the optical axis and connects its upper ends and a lower opening that connects its lower ends; and a third reflector having a reflecting surface inside the second reflector that surrounds the optical axis and connects its upper ends and a lower opening that connects its lower ends, Among the light rays traveling from the end of the light-emitting region toward the first reflector, there are light rays that are reflected by the first reflector and then strike a rear surface of the second reflector, a light ray traveling from an end of the light emitting region toward the second reflector is incident on the inside of the second reflector, A light ray traveling from an end of the light emitting region toward the third reflector is incident on the rear surface of the third reflector. Lighting equipment.

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