Light-emitting device and lighting fixture

Abstract

To provide a light-emitting device that can adjust the color temperature with consideration for the circadian rhythm through mixed light of two types of light, and that satisfies the requirements for high color rendering Class 3.SOLUTION: The light-emitting device includes one or more LED elements and a plurality of phosphors, and emits high color temperature light having a color temperature of 7500 K or higher, and low color temperature light having a color temperature of 2000 K to 3000 K. The mixed light of the high color temperature light and the low color temperature light has an average color rendering index Ra of 95 or higher and a special color rendering index R9 of 75 or higher within a color temperature range from 2700 K to 7500 K, and has a melanopic ratio exceeding 1 at a color temperature of 6000 K or higher.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a light-emitting device and a lighting fixture that take into consideration human circadian rhythms and color rendering properties. [Background technology]

[0002] In lighting and displays, some practices have begun to adjust color temperature to take circadian rhythms into consideration.

[0003] Also, it has long been common to consider color rendering, which affects how things appear. According to JIS Z 9112:2019 (Classification of fluorescent lamps and LEDs by light source color and color rendering), if a lamp meets the following criteria within the color temperature range (2600K to 7100K), an average color rendering index Ra of 95 or higher and a special color rendering index R9 (red) of 75 or higher, it is classified as high color rendering class 3 (a class recommended for displaying and appreciating art works in art galleries and museums).

[0004] Light emitting devices that can adjust color temperature in consideration of circadian rhythms and that also take color rendering into account are known, such as those disclosed in Patent Document 1. However, as shown in Fig. 12, even the second light emitting device, which is the light emitting device that takes color rendering into account the most among the first to third light emitting devices according to the embodiments of Patent Document 1, has an R9 of 68 for warm white light (around 2700K), and does not satisfy the requirement of an R9 of 75 or more over the color temperature range (2600K to 7100K). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7174266 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, an object of the present invention is to provide a light emitting device that can adjust the color temperature by mixing two types of light, taking into consideration the circadian rhythm, and that easily meets the high color rendering class 3 standard. [Means for solving the problem]

[0007] [1] A light emitting diode (LED) lamp comprising one or more LED elements and a plurality of phosphors; It emits light on the high color temperature side with a color temperature of 7500K or more and light on the low color temperature side with a color temperature of 2000 to 3000K, The mixed light of the high color temperature light and the low color temperature light has a color temperature in the range of 2700 to 7500K, an average color rendering index Ra of 95 or more, and a special color rendering index R9 (red) of 75 or more, and a color temperature of 6000K or more and a melanopic ratio of more than 1.

[0008] [2] One or more LED elements and a plurality of phosphors; It emits light on the high color temperature side with a color temperature of 7500K or more and light on the low color temperature side with a color temperature of 2000 to 3000K, The mixed light of the high color temperature side light and the low color temperature side light has chromaticity coordinates on the CIE 1931 color system chromaticity diagram (hereinafter simply referred to as "chromaticity diagram") such that x is within the range of 0.295 to 0.298 and y is within the range of 0.315 to 0.331 (more preferably, x is within the range of 0.295 to 0.297 and y is within the range of 0.324 to 0.330) at a color temperature of 7500K, and x is within the range of 0.462 to 0.467 and y is within the range of 0.415 to 0.425 (more preferably, x is within the range of 0.463 to 0.466 and y is within the range of 0.416 to 0.421) at a color temperature of 2700K.

[0009] [3] One or more LED elements and a plurality of phosphors; It emits light on the high color temperature side with a color temperature of 7500K or more and light on the low color temperature side with a color temperature of 2000 to 3000K, The mixed light of the high color temperature side light and the low color temperature side light has chromaticity coordinates in the chromaticity diagram where x is within the range of 0.295 to 0.298 and y is within the range of 0.315 to 0.331 (more preferably, x is within the range of 0.295 to 0.297 and y is within the range of 0.324 to 0.330) at a color temperature of 7500K, and where x is within the range of 0.462 to 0.467 and y is within the range of 0.415 to 0.425 (more preferably, x is within the range of 0.463 to 0.466 and y is within the range of 0.416 to 0.421) at a color temperature of 2700K, The mixed light has a color temperature in the range of 2700 to 7500K, an average color rendering index Ra of 95 or more, and a special color rendering index R9 of 75 or more, and a color temperature of 6000K or more and a melanopic ratio of more than 1.

[0010] [4] A lighting fixture comprising the light-emitting device according to any one of [1] to [3] above. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a light emitting device that can adjust the color temperature by mixing two types of light in consideration of the circadian rhythm and that satisfies high color rendering class 3. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view of the light emitting devices of the example and the comparative example. [Figure 2] 2(a) is an emission spectrum diagram of light (8200K) on the high color temperature side of Example 1, and FIG. 2(b) is an emission spectrum diagram of light (2400K) on the low color temperature side of Example 1. [Figure 3] FIG. 3 is a diagram showing the emission spectrum of mixed light (7 levels: 7500K, 6700K, 5400K, 4500K, 3800K, 3100K, 2700K) of high color temperature light and low color temperature light in Example 1. [Figure 4] FIG. 4 is a chromaticity diagram showing the chromaticity coordinates of the mixed light (seven stages) of each example and each comparative example. [Figure 5] FIG. 5 is an enlarged chromaticity diagram showing the chromaticity coordinates of the mixed light (7500K) of each example and each comparative example. [Figure 6] FIG. 6 is an enlarged chromaticity diagram showing the chromaticity coordinates of the mixed light (2700K) of each example and each comparative example. [Figure 7] FIG. 7 is a diagram showing the emission spectrum of the mixed light (seven stages) of the high color temperature side light and the low color temperature side light in Example 2. [Figure 8] 8(a) is an emission spectrum diagram of light (10300K) on the high color temperature side of Comparative Example 1, and FIG. 8(b) is an emission spectrum diagram of light (2500K) on the low color temperature side of Comparative Example 1. FIG. [Figure 9] FIG. 9 is a diagram showing the emission spectrum of the mixed light (seven stages) of the high color temperature light and the low color temperature light of Comparative Example 1. [Figure 10] FIG. 10 is a graph showing R9 of the mixed light (seven stages) of Examples 1 to 4. [Figure 11] FIG. 11 is a graph showing R9 of the mixed light (seven stages) of Comparative Examples 1 to 3. [Figure 12] FIG. 12 is a graph showing R9 of light (6500K, 5000K, 4000K, 3500K, 3000K, 2700K) from the light emitting device of Patent Document 1. DETAILED DESCRIPTION OF THE INVENTION

[0013] <1> LED element The LED element includes a laser diode element. The peak wavelength emitted by the LED element is not particularly limited, but is preferably 450 nm or less.

[0014] <2> phosphor Phosphors are substances that emit fluorescence when excited by the light emitted by the LED element. The phosphor is preferably a phosphor group consisting of multiple types of phosphors. The phosphor for emitting light on the high color temperature side preferably includes at least one blue phosphor having a peak wavelength in the range of 445 to 490 nm and at least one yellow to green phosphor having a peak wavelength in the range of 491 to 600 nm. The phosphor for emitting light on the low color temperature side preferably includes at least one yellow to green phosphor having a peak wavelength in the range of 491 to 600 nm and at least one red phosphor having a peak wavelength in the range of 601 to 670 nm.

[0015] <3> One or more LED elements and multiple phosphors "One or more LED elements and multiple phosphors" includes the following embodiments. An LED element and a plurality of phosphors separated from each other so as to be excited separately by the light emitted by the LED element. a first LED element, a first phosphor excited by light emitted from the first LED element, a second LED element, and a second phosphor excited by light emitted from the second LED element;

[0016] <4> Two Lights If the mixed light is made up of two lights, one on the high color temperature side and the other on the low color temperature side, and has a color temperature in the range of 2700 to 7500K, an average color rendering index Ra of 95 or more, a special color rendering index R9 of 75 or more, and a color temperature of 6000K or more, and a melanopic ratio of more than 1, then a third light may be added to and mixed with the two lights to further enhance the color rendering properties.

[0017] <5> Melanopic ratio Circadian-friendly lighting regulates circadian rhythms by irradiating low-intensity light with a high color temperature that suppresses melatonin secretion in the morning, and low-intensity light with a low color temperature that promotes melatonin secretion in the evening. WELL certification began in the United States, and for lighting in buildings and offices, the standard for receiving high points is "a minimum vertical illuminance of 240 EML between the hours of 9:00 AM and 1:00 PM." EML is a unit of measurement for equivalent melanopic illuminance, and is calculated using a melanopic sensitivity curve that peaks at a wavelength of 490 nm (see Figures 2 and 8), as opposed to the usual luminosity curve that peaks at a wavelength of 555 nm.

[0018] Equivalent melanopic illuminance is expressed as "equivalent melanopic illuminance = illuminance × melanopic ratio." If the spectral distribution curve of the light source is E(λ), the melanopic sensitivity curve is C(λ), and the luminosity curve is V(λ), the melanopic ratio is expressed by the following formula (1).

[0019]

number

[0020] Next, examples embodying the present invention will be described with reference to the drawings, while comparing them with comparative examples. Note that the materials, quantities, and conditions of each part in the examples are examples and can be changed as appropriate without departing from the scope of the invention.

[0021] As shown in Fig. 1, the light emitting device 1 of the embodiment includes a substrate 10, a first LED element 2 bonded onto the substrate 10, a first sealing material 3 that seals the first LED element 2, a second LED element 6 bonded onto the substrate 10, and a second sealing material 7 that seals the second LED element 6. The first sealing material 3 is made of a transparent resin 4 and a phosphor 5 dispersed in the resin 4. The second sealing material 7 is made of a transparent resin 8 and a phosphor 9 dispersed in the resin 8.

[0022] The light emitting device 1 of the embodiment emits high color temperature light with a color temperature of 7500K or higher using the first LED element 2 and phosphor 5, and emits low color temperature light with a color temperature in the range of 2000K-3000K using the second LED element 6 and phosphor 9. The mixed light of the high color temperature light and the low color temperature light satisfies Ra≧95 and R9≧75 at a color temperature in the range of 2700K-7500K, and has a melanopic ratio of greater than 1 at a color temperature of 6000K or higher. In contrast, the light emitting device of the comparative example has the same structure as that of the example shown in FIG. 1, but the light characteristics are different from those of the example. Specifically, the light emitting devices of Examples 1 to 4 and Comparative Examples 1 to 3 shown in Table 1 were fabricated as follows, and the optical characteristics were examined.

[0023] [Table 1]

[0024] In Table 1, the LED element is a gallium nitride LED element manufactured by Toyoda Gosei Co., Ltd. The resin used is silicone resin T-122 manufactured by Aica Kogyo Co., Ltd. VB202A3 is the product number of a blue phosphor (SBCA) manufactured by Mitsubishi Chemical Corporation. VB202B3 is the product number of a blue phosphor (SBCA) manufactured by Mitsubishi Chemical Corporation. GR540K is the product number for a green phosphor (β-sialon) manufactured by Denka. YL595B is the product number for an orange phosphor (α-sialon) manufactured by Denka. VR-103C is the product number for a red phosphor (CASN) manufactured by Mitsubishi Chemical Corporation. R660 is the product number of a red phosphor (CASN) manufactured by Denka.

[0025] [Example 1] (Production method) A first LED element 2 and a second LED element 6 are mounted side by side on a substrate 10 and can be energized. Both LED elements 2 and 6 emit light with a peak wavelength of 400 to 410 nm. Here, LED elements with the same peak wavelength are used for the first LED element 2 for light on the high color temperature side and the second LED element 6 for light on the low color temperature side, but LED elements with different peak wavelengths may also be used. The phosphors shown in the top row of Table 1 (HT: high color temperature light) were blended into the resin in the amounts per 1 g of resin, and the mixture was mixed using a stirrer or similar to uniformly disperse the phosphors in the resin. This mixture of resin and phosphor was applied to the first LED element 2 in the amount shown in Table 1 using a dispenser or similar. The phosphors shown in the lower row of Table 1 (LT: light on the low color temperature side) were blended into the resin in the amounts per 1 g of resin, and the mixture was mixed using a stirrer or similar to uniformly disperse the phosphors in the resin. This mixture of resin and phosphor was applied onto the second LED element 6 in the amount shown in Table 1 using a dispenser or similar. The resin was heated and cured in an oven to form the first sealing material 3 and the second sealing material 7, and the light emitting device 1 was fabricated.

[0026] (Two light emission spectra and color temperatures) Figure 2(a) shows the emission spectrum of the "high color temperature light" emitted by the first LED element 2 and phosphor 5 when only the first LED element 2 is energized. As shown in Table 1, the color temperature of the high color temperature light is 8200K. Figure 2(b) shows the emission spectrum of the "low color temperature light" emitted by the second LED element 6 and phosphor 9 when only the second LED element 6 is energized. As shown in Table 1, the color temperature of the low color temperature light is 2400K.

[0027] (mixed light) The first LED element 2 and the second LED element 6 were simultaneously energized, and the ratio of the two currents was varied from 1:0 to 0:1, to vary the color temperature of the "mixed light" (higher and lower color temperature lights) from 7500K to 2700K. The emission spectra for each of the seven mixed light color temperatures (7500K, 6700K, 5400K, 4500K, 3800K, 3100K, and 2700K) are shown in Figure 3, the chromaticity coordinates on the chromaticity diagram are shown in Tables 2 and 4, and the Ra, R9, and melanopic ratio are shown in Table 2. The chromaticity coordinates for the 7500K color temperature are also shown in an enlarged view in Figure 5, and the chromaticity coordinates for the 2700K color temperature are also shown in an enlarged view in Figure 6.

[0028] [Table 2]

[0029] [Example 2] Light emitting devices were fabricated in the same manner as in Example 1, except that the selection, blending amount, and coating amount of the phosphor were changed as shown in Table 1. As shown in Table 1, the color temperature of the light on the high color temperature side is 10600K, and the color temperature of the light on the low color temperature side is 2300K. As in Example 1, the current ratio was changed to vary the color temperature of the "mixed light" of the high color temperature light and the low color temperature light within the range of 7500K to 2700K. The emission spectrum for each of the seven color temperatures of the mixed light is shown in FIG. 7, the chromaticity coordinates on the chromaticity diagram are shown in Tables 3 and 4, and the Ra, R9, and melanopic ratio are shown in Table 3. The chromaticity coordinates for a color temperature of 7500K are also shown in an enlarged view in FIG. 5, and the chromaticity coordinates for a color temperature of 2700K are also shown in an enlarged view in FIG. 6.

[0030] [Table 3]

[0031] [Example 3] Light emitting devices were fabricated in the same manner as in Example 1, except that the selection, blending amount, and coating amount of the phosphor were changed as shown in Table 1. As shown in Table 1, the color temperature of the light on the high color temperature side is 9500K, and the color temperature of the light on the low color temperature side is 2300K. Furthermore, as in Example 1, the current ratio was changed, and the color temperature of the "mixed light" of the high color temperature light and the low color temperature light was changed in the range from 7500K to 2700K. The chromaticity coordinates on the chromaticity diagram for each of the seven levels of color temperature of the mixed light are shown in Table 4 and Figure 4, and the Ra, R9, and melanopic ratio are also shown in Table 4. The chromaticity coordinates for a color temperature of 7500K are also shown in an enlarged view in Figure 5, and the chromaticity coordinates for a color temperature of 2700K are also shown in an enlarged view in Figure 6.

[0032] [Table 4]

[0033] [Example 4] Light emitting devices were fabricated in the same manner as in Example 1, except that the selection, blending amount, and coating amount of the phosphor were changed as shown in Table 1. As shown in Table 1, the color temperature of the light on the high color temperature side is 9200K, and the color temperature of the light on the low color temperature side is 2300K. Furthermore, as in Example 1, the current ratio was changed, and the color temperature of the "mixed light" of the high color temperature light and the low color temperature light was changed in the range from 7500K to 2700K. The chromaticity coordinates on the chromaticity diagram for each of the seven levels of color temperature of the mixed light are shown in Table 5 and Figure 4, and the Ra, R9, and melanopic ratio are also shown in Table 5. The chromaticity coordinates for a color temperature of 7500K are also shown in an enlarged view in Figure 5, and the chromaticity coordinates for a color temperature of 2700K are also shown in an enlarged view in Figure 6.

[0034] [Table 5]

[0035] [Comparative Example 1] Light emitting devices were fabricated in the same manner as in Example 1, except that the selection, blending amount, and coating amount of the phosphor were changed as shown in Table 1. The emission spectrum of the "high color temperature light" is shown in Figure 8(a). As shown in Table 1, the color temperature of the high color temperature light is 10,300K. The emission spectrum of the "low color temperature light" is shown in Figure 8(b). As shown in Table 1, the color temperature of the low color temperature light is 2500K. As in Example 1, the current ratio was changed to vary the color temperature of the "mixed light" of the high color temperature light and the low color temperature light within the range of 7500K to 2700K. The emission spectrum for each of the seven color temperatures of the mixed light is shown in FIG. 9, the chromaticity coordinates on the chromaticity diagram are shown in Table 6 and FIG. 4, and the Ra, R9, and melanopic ratio are shown in Table 6. The chromaticity coordinates for a color temperature of 7500K are also shown in an enlarged view in FIG. 5, and the chromaticity coordinates for a color temperature of 2700K are also shown in an enlarged view in FIG. 6.

[0036] [Table 6]

[0037] Comparative Example 2 Light emitting devices were fabricated in the same manner as in Comparative Example 1, except that the selection, blending amount, and coating amount of the phosphor were changed as shown in Table 1. As shown in Table 1, the color temperature of the light on the high color temperature side is 9600K, and the color temperature of the light on the low color temperature side is 2300K. Furthermore, as in Example 1, the current ratio was changed to vary the color temperature of the "mixed light" of the high color temperature light and the low color temperature light within the range of 7500K to 2700K. The chromaticity coordinates on the chromaticity diagram for each of the seven levels of color temperature of the mixed light are shown in Table 7 and Figure 4, and the Ra, R9, and melanopic ratio are also shown in Table 7. The chromaticity coordinates for a color temperature of 7500K are also shown in an enlarged view in Figure 5, and the chromaticity coordinates for a color temperature of 2700K are also shown in an enlarged view in Figure 6.

[0038] [Table 7]

[0039] Comparative Example 3 Light emitting devices were fabricated in the same manner as in Comparative Example 1, except that the selection, blending amount, and coating amount of the phosphor were changed as shown in Table 1. As shown in Table 1, the color temperature of the light on the high color temperature side is 8500K, and the color temperature of the light on the low color temperature side is 2100K. Furthermore, as in Example 1, the current ratio was changed, and the color temperature of the "mixed light" of the high color temperature light and the low color temperature light was changed in the range of 7500K to 2700K. The chromaticity coordinates on the chromaticity diagram for each of the seven color temperatures of the mixed light are shown in Table 8 and Figure 4, and the Ra, R9, and melanopic ratio are also shown in Table 8. The chromaticity coordinates for a color temperature of 7500K are also shown in an enlarged view in Figure 5, and the chromaticity coordinates for a color temperature of 2700K are also shown in an enlarged view in Figure 6.

[0040] [Table 8]

[0041] [summary] The mixed light of high color temperature light and low color temperature light in Comparative Examples 1 to 3 did not satisfy the requirements of Ra of 95 or more and R9 of 75 or more in the color temperature range of 2700 to 7500 K. R9 is summarized in Figure 11 for ease of understanding. In contrast, the mixed light of high and low color temperature lights in Examples 1 to 4 satisfied the requirements of Ra of 95 or greater and R9 of 75 or greater at color temperatures ranging from 2700 to 7500 K. R9 is summarized in Figure 10 for clarity. Furthermore, as shown in Figures 5 and 6, the above requirements are estimated to be met if, in chromaticity coordinates, x is within the range of 0.295 to 0.298 and y is within the range of 0.315 to 0.331 at a color temperature of 7500 K, and x is within the range of 0.462 to 0.467 and y is within the range of 0.415 to 0.425 at a color temperature of 2700 K. Furthermore, Tables 2 to 5 indicate that the melanopic ratio exceeds 1 at color temperatures of 6000 K or greater, indicating that the light-emitting device takes circadian rhythm into consideration.

[0042] The present invention is not limited to the above-described embodiments, and can be embodied by making appropriate modifications within the scope of the gist of the invention. [Explanation of symbols]

[0043] 1. Light-emitting device 2. First LED element 3. First sealing material 4. Resin 5. Phosphors 6 Second LED element 7 Second sealing material 8. Resin 10 Substrate

Claims

1. The present invention comprises one or more LED elements having a peak wavelength of 410 nm or less, and a phosphor group including at least a plurality of blue phosphors, The light source emits light on the high color temperature side having a color temperature of 7500K or more and light on the low color temperature side having a color temperature of 2000 to 3000K, The mixed light of the high color temperature side light and the low color temperature side light has a color temperature in the range of 2700 to 7500K, an average color rendering index Ra of 95 or more, and a special color rendering index R9 of 75 or more, and a color temperature of 6000K or more and a melanopic ratio of more than 1.

2. The present invention comprises one or more LED elements having a peak wavelength of 410 nm or less, and a phosphor group including at least a plurality of blue phosphors, The light source emits light on the high color temperature side having a color temperature of 7500K or more and light on the low color temperature side having a color temperature of 2000 to 3000K, The mixed light of the light on the high color temperature side and the light on the low color temperature side is such that, in chromaticity coordinates of the chromaticity diagram of the CIE 1931 color system, x is in the range of 0.295 to 0.298 and y is in the range of 0.315 to 0.331 at a color temperature of 7500K, and x is in the range of 0.462 to 0.467 and y is in the range of 0.415 to 0.425 at a color temperature of 2700K.

3. The present invention comprises one or more LED elements having a peak wavelength of 410 nm or less, and a phosphor group including at least a plurality of blue phosphors, The light source emits light on the high color temperature side having a color temperature of 7500K or more and light on the low color temperature side having a color temperature of 2000 to 3000K, The mixed light of the high color temperature side light and the low color temperature side light has chromaticity coordinates in the chromaticity diagram of the CIE 1931 color system where x is in the range of 0.295 to 0.298 and y is in the range of 0.315 to 0.331 at a color temperature of 7500 K, and where x is in the range of 0.462 to 0.467 and y is in the range of 0.415 to 0.425 at a color temperature of 2700 K, The mixed light has a color temperature in the range of 2700 to 7500K, an average color rendering index Ra of 95 or more, and a special color rendering index R9 of 75 or more, and a color temperature of 6000K or more and a melanopic ratio of more than 1.

4. A lighting fixture comprising the light-emitting device according to any one of claims 1 to 3.

Images