Light-emitting device and lighting fixture

Abstract

To provide a light-emitting device that can adjust color temperature by mixing two types of light, taking into consideration the circadian rhythm, and meets high color rendering class 3 standards. [Solution] A light-emitting device comprising one or more LED elements and multiple phosphors, which emits high color temperature light with a color temperature of 7500K or higher and low color temperature light with a color temperature of 2000 to 3000K, wherein 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 higher and a special color rendering index R9 of 75 or higher, and has a color temperature of 6000K or higher and a melanopic ratio exceeding 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 with consideration for circadian rhythms.

[0003] Also, it has been common practice to take into consideration color rendering, which affects how things look. In JIS Z 9112:2019 (Classification of fluorescent lamps and LEDs by light source color and color rendering), if the average color rendering index Ra is 95 or more in the color temperature range (2600K to 7100K) and the special color rendering index R9 (red) is 75 or more, the lamp will be classified as high color rendering class 3 (a class recommended for displaying and appreciating artworks 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 consideration are known, such as in Patent Document 1. However, as shown in Fig. 12, even the second light emitting device that takes color rendering into consideration the most among the first to third light emitting devices according to the embodiment of Patent Document 1 has an R9 of 68 for incandescent light (around 2700K), and does not meet the requirement of an R9 of 75 or more in 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 7500 K, an average color rendering index Ra of 95 or more, a special color rendering index R9 (red) of 75 or more, and a color temperature of 6000 K or more and a melanopic ratio exceeding 1.

[0008] [2] 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 light on the high color temperature side and the light on the low color temperature side is such that, in terms of chromaticity coordinates on the chromaticity diagram of the CIE 1931 color system (hereinafter simply referred to as the "chromaticity diagram"), x is within the ranges of 0.295 to 0.298 and y is within the ranges of 0.315 to 0.331 (more preferably, x is within the ranges of 0.295 to 0.297 and y is within the ranges of 0.324 to 0.330) at a color temperature of 7500 K, and x is within the ranges of 0.462 to 0.467 and y is within the ranges of 0.415 to 0.425 (more preferably, x is within the ranges of 0.463 to 0.466 and y is within the ranges of 0.416 to 0.421) at a color temperature of 2700 K.

[0009] [3] 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 light on the high color temperature side and the light on the low color temperature side has, in terms of chromaticity coordinates on the chromaticity diagram, x in the range of 0.295 to 0.298 and y in the range of 0.315 to 0.331 (more preferably, x in the range of 0.295 to 0.297 and y in the range of 0.324 to 0.330) at a color temperature of 7500 K, and x in the range of 0.462 to 0.467 and y in the range of 0.415 to 0.425 (more preferably, x in the range of 0.463 to 0.466 and y in the range of 0.416 to 0.421) at a color temperature of 2700 K, The mixed light is a light-emitting device having 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 exceeding 1.

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

[0011] According to the present invention, 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 can be provided. [Brief description 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. [Diagram 2] FIG. 2(a) is an emission spectrum diagram of light (8200 K) on the high color temperature side of Example 1, and FIG. 2(b) is an emission spectrum diagram of light (2400 K) on the low color temperature side of Example 1. [Diagram 3] FIG. 3 is an emission spectrum diagram of the 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 (the above-mentioned seven stages) of each of the examples and each of the comparative examples. [Diagram 5] FIG. 5 is an enlarged chromaticity diagram showing the chromaticity coordinates of the mixed light (7500K) of each of the examples and each of the comparative examples. [Figure 6] FIG. 6 is an enlarged chromaticity diagram showing the chromaticity coordinates of the mixed light (2700K) of each of the examples and each of the comparative examples. [Figure 7] FIG. 7 is an emission spectrum diagram of the mixed light (seven stages) of the high color temperature light and the low color temperature light in Example 2. [Figure 8] FIG. 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. [Figure 9] FIG. 9 is an emission spectrum diagram of the mixed light (the above-mentioned 7 stages) of light on the high color temperature side and light on the low color temperature side in Comparative Example 1. [Figure 10] FIG. 10 is a graph showing R9 of the mixed light (the above-mentioned seven stages) of Examples 1 to 4. [Figure 11] FIG. 11 is a graph showing R9 of the mixed light (the above-mentioned seven stages) of Comparative Examples 1 to 3. [Figure 12] FIG. 12 is a graph showing R9 of the light (6500K, 5000K, 4000K, 3500K, 3000K, 2700K) of the light emitting device of Patent Document 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 A phosphor is a substance that emits fluorescence when excited by the light emitted by an LED element. The phosphor is preferably a phosphor group consisting of a plurality of types of phosphors. The phosphor for emitting light on the high color temperature side preferably includes at least one each of a blue phosphor having a peak wavelength in the range of 445 to 490 nm and a 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 each of a yellow to green phosphor having a peak wavelength in the range of 491 to 600 nm and a 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 a mixture of two lights, one on the high color temperature side and the other on the low color temperature side, has a color temperature in the range of 2700 to 7500 K, 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 6000 K or more and a melanopic ratio of more than 1, a third light may be added to and mixed with the two lights to further improve the color rendering.

[0017] <5> Melanopic Ratio Circadian-friendly lighting is lighting that regulates the circadian rhythm by irradiating light with a high color temperature at low illuminance in the morning, which suppresses the secretion of melatonin, and irradiating light with a low color temperature at low illuminance in the evening, which causes the secretion of melatonin. WELL certification began in the United States, and for lighting in buildings and offices, the standard for obtaining high points is set as "having a vertical illuminance of at least 240 EML between 9:00 a.m. and 1:00 p.m." EML is a unit of equivalent melanopic illuminance, and is an illuminance calculated using a melanopic sensitivity curve with a peak at a wavelength of 490 nm (see Figures 2 and 8), which is different from the usual luminosity curve with a peak at a wavelength of 555 nm.

[0018] Equivalent melanopic illuminance is expressed as "equivalent melanopic illuminance = illuminance × melanopic ratio", and 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 merely examples, and can be appropriately changed without departing from the gist of the invention.

[0021] 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 having a color temperature of 7500K or higher using a first LED element 2 and phosphor 5, and emits low color temperature light having a color temperature in the range of 2000K-3000K using a second LED element 6 and phosphor 9. The mixed light of the high color temperature light and the low color temperature light has a color temperature in the range of 2700K-7500K and satisfies Ra≧95 and R9≧75, and has a color temperature of 6000K or higher and a melanopic ratio exceeding 1. In contrast, the light emitting device of the comparative example has the same structure as that of the embodiment shown in FIG. 1, but has different optical characteristics from that of the embodiment. 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 for a blue phosphor (SBCA) manufactured by Mitsubishi Chemical Corporation. VB202B3 is the product number for 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, 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 upper row of Table 1 (HT: high color temperature light) were mixed into the resin in the amounts per 1 g of resin, and the mixture was mixed using a stirrer or similar device to uniformly disperse the phosphors in the resin. This mixture of resin and phosphors was applied onto the first LED element 2 in the amount shown in Table 1 using a dispenser or similar device. The phosphors shown in the lower row of Table 1 (LT: light on the low color temperature side) were mixed into the resin in the amounts per gram of resin, and the mixture was mixed using a stirrer or the like to uniformly disperse the phosphors in the resin. This mixture of resin and phosphors was applied onto the second LED element 6 in the amount shown in Table 1 using a dispenser or the like. 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 produced.

[0026] (Emission spectrum and color temperature of two lights) 2(a) shows the emission spectrum of the "high color temperature light" emitted by the first LED element 2 and the 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. 2(b) shows the emission spectrum of the "low color temperature light" emitted by the second LED element 6 and the 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 changed from 1:0 to 0:1, and the color temperature of the "mixed light" of the high color temperature side light and the low color temperature side light was changed in the range from 7500K to 2700K. The emission spectrum when the color temperature of the mixed light was 7500K, 6700K, 5400K, 4500K, 3800K, 3100K, and 2700K is shown in FIG. 3, the chromaticity coordinates in the chromaticity diagram are shown in Tables 2 and 4, and Ra, R9, and the melanopic ratio are shown in Table 2. The chromaticity coordinates when the color temperature was 7500K are also shown in an enlarged view in FIG. 5, and the chromaticity coordinates when the color temperature was 2700K are also shown in an enlarged view in FIG. 6.

[0028] [Table 2]

[0029] [Example 2] A light emitting device was 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 10,600K, and the color temperature of the light on the low color temperature side is 2,300K. Similarly to 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 emission spectrum for each of the seven stages of color temperature of the mixed light is shown in FIG. 7, the chromaticity coordinates in the chromaticity diagram are shown in Tables 3 and 4, and Ra, R9, and the 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] A light emitting device was 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. Similarly to 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 in the chromaticity diagram for each of the seven stages of mixed light color temperature are shown in Table 4 and Figure 4, and the Ra, R9, and melanopic ratio are 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] A light emitting device was 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. Similarly to 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 in the chromaticity diagram for each of the seven stages of mixed light color temperature are shown in Table 5 and Figure 4, and the Ra, R9, and melanopic ratio are 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] A light emitting device was 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. Similarly to 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 emission spectrum for each of the seven stages of color temperature of the mixed light is shown in FIG. 9, the chromaticity coordinates in the chromaticity diagram are shown in Table 6 and FIG. 4, and Ra, R9, and the 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. Similarly to 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 in the chromaticity diagram for each of the seven stages of color temperature of the mixed light are shown in Table 7 and Figure 4, and the Ra, R9, and melanopic ratio are 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. Similarly to 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 in the chromaticity diagram for each of the seven stages of mixed light color temperature are shown in Table 8 and Figure 4, and the Ra, R9, and melanopic ratio are 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 FIG. 11 for ease of understanding. In contrast, the mixed light of the high color temperature side light and the low color temperature side light of Examples 1 to 4 satisfied Ra of 95 or more and R9 of 75 or more in the color temperature range of 2700 to 7500K. R9 is summarized in FIG. 10 for easy understanding. ●Also, as shown in FIG. 5 and FIG. 6, it is estimated that the above satisfaction is obtained if, in the 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 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 at a color temperature of 2700K. Also, from Tables 2 to 5, it is estimated that the melanopic ratio exceeds 1 in the color temperature range of 6000K or more, so it can be said that the light-emitting device takes circadian rhythm into consideration.

[0042] The present invention is not limited to the above-described embodiment, and can be embodied by making appropriate modifications without departing from 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 includes one or more LED elements and a plurality of phosphors, The light emitting device 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 melanopic ratio of 1 or more at a color temperature of 6000K or more, and a melanopic ratio of 0.58 or less at a color temperature of 3100K.

2. The present invention includes one or more LED elements and a plurality of phosphors, The light emitting device 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 chromaticity coordinate of x in the range of 0.295 to 0.298 and y in the range of 0.315 to 0.331 at a color temperature of 7500K, and has a chromaticity coordinate of x in the range of 0.462 to 0.467 and y in the range of 0.415 to 0.425 at a color temperature of 2700K, The mixed light is a light-emitting device having 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, and a color temperature of 3100K and a melanopic ratio of not more than 0.

58.

3. A lighting fixture comprising the light-emitting device according to claim 1 or 2.

Images