LED light-emitting device, lighting fixture, and measurement light source

Abstract

To provide an LED light-emitting device that satisfies both broadband characteristics and high color rendering properties.SOLUTION: An LED light emitting device includes one or a plurality of LED elements and a plurality of phosphors, and extracted light from the LED light emitting device has a continuous emission spectrum in a wavelength range of 450 to 950 nm, and has a color temperature in a range of 2500 to 5000 K, an average color rendering index Ra of 90 or more, and a special color rendering index R15 of 88 or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an LED light-emitting device, a lighting fixture, and a measurement light source that take into consideration broadband and high color rendering properties. [Background technology]

[0002] The replacement of halogen lamps with energy-efficient LED light-emitting devices is progressing rapidly in various lighting applications, but progress has not been sufficient in applications requiring broadband and high color rendering, as it is difficult for LED light-emitting devices to satisfy both of these characteristics.

[0003] Regarding broadband performance, Patent Document 1 describes an LED light-emitting device that has a continuous spectrum over a broad band (400 to 1000 nm) by using an LED that emits light with a peak wavelength in the range of 480 nm or less and a near-infrared phosphor that emits light with a peak wavelength in the range of over 700 nm and a full width at half maximum of 100 nm or more. This LED light-emitting device is said to be suitable for use as a light-emitting device for industrial equipment such as spectroscopic analyzers. However, Patent Document 1 does not describe color rendering properties.

[0004] Patent Document 2 describes an ultra-broadband LED light-emitting device that uses a white LED chip and a near-infrared phosphor, selecting the near-infrared phosphor from the group consisting of a first phosphor with an emission peak at 710 nm, a second phosphor with an emission peak at 810 nm, and a third phosphor with an emission peak at 910 nm, thereby covering a wavelength range of 380 to 1200 nm. This LED light-emitting device is said to be able to replace halogen lamps and to have a spectral distribution similar to that of sunlight. However, the average color rendering index Ra of Samples A, B, and C in the example was only 83 to 87, and the specific color rendering index R9 was only 37 to 52 (Table 3), indicating poor color rendering.

[0005] On the other hand, LED light-emitting devices with high color rendering properties are known in the normal wavelength range (400 to 750 nm). For example, Patent Document 3 describes an LED light-emitting device with high color rendering properties, which includes an LED having an emission peak wavelength in the range of 430 to 470 nm and a fluorescent member including at least one phosphor selected from a first phosphor, a second phosphor, and a third phosphor having a predetermined composition, and which includes two or more rare earth aluminate phosphors, a fourth phosphor having a predetermined composition, and a fifth phosphor having a predetermined composition. In the examples, the LED light-emitting device exhibits high color rendering properties, with an Ra of 93.9 to 95.9 and an R15 of 93.2 to 96.0 (Table 2). However, the emission in this example is in the normal wavelength range of 400 to 750 nm (Figures 2 to 7), and does not have broadband capability extending into the near-infrared region. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 7428323 [Patent Document 2] Patent No. 2022-553359 [Patent Document 3] Patent No. 7311819 Summary of the Invention [Problem to be solved by the invention]

[0007] As mentioned above, it is difficult for an LED light-emitting device to satisfy both broadband and high color rendering. Furthermore, according to the study by the present inventors, if a near-infrared phosphor having an emission intensity around 800 nm as in Patent Documents 1 and 2 is added to an LED light-emitting device that has high color rendering in the normal band as in Patent Document 3 in order to give it broadband performance up to the near-infrared region, it was found that high color rendering cannot be maintained because the human eye perceives light from 640 to 770 nm as red.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an LED light-emitting device that satisfies both broadband characteristics and high color rendering properties. [Means for solving the problem]

[0009] [1] An LED light emitting device comprising one or more LED elements and multiple phosphors, The light extracted from the light-emitting device has a continuous emission spectrum in the wavelength range of 450 to 950 nm, and the color temperature is in the range of 2500 to 5000 K, with an average color rendering index Ra of 90 or more and a special color rendering index R15 of 88 or more.

[0010] [2] The LED light-emitting device according to [1], wherein the extracted light has emission peaks at 770 to 820 nm and 550 to 650 nm, and the maximum emission peak intensity (B) at 550 to 650 nm is higher than the maximum emission peak intensity (A) at 770 to 820 nm.

[0011] [3] The LED light-emitting device according to [2], wherein the ratio (B / A) of the maximum emission peak intensity (B) at 550 to 650 nm to the maximum emission peak intensity (A) at 770 to 820 nm is 1.03 to 1.55.

[0012] [4] An LED light-emitting device according to [1] or [2], wherein the chromaticity point of the extracted light in the chromaticity diagram of the CIE 1931 color system (hereinafter simply referred to as the "chromaticity diagram") is located below the blackbody radiation locus.

[0013] [5] An LED light emitting device that includes one or more LED elements and multiple phosphors and emits white light, The LED element has an emission peak at 440 to 460 nm, The phosphor includes a green phosphor having an emission peak in the range of 480 to 520 nm, a red phosphor having an emission peak in the range of 640 to 680 nm, and a near-infrared phosphor having an emission peak in the range of 780 to 820 nm, The green phosphor is Lu3Al5O 12 :Ce 3+ It has a composition represented by The red phosphor is CaAlSiN3:Eu 2+ It has a composition represented by The near-infrared phosphor is Li a Sr b Lac Si d N e EU f (wherein a to f are numbers that satisfy a+b+c+d+e+f=100, 0≦a≦8.22, 0.22≦b≦17.33, 1.12≦c≦11.36, 22.41≦d≦38.09, 49.47≦e≦56.09, 0.88≦f≦1.01.)

[0014] [6] A lighting fixture comprising the LED light-emitting device according to any one of [1] to [5] above.

[0015] [7] A measurement light source comprising the LED light emitting device according to any one of [1] to [5] above. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide an LED light-emitting device that satisfies both broadband characteristics and high color rendering properties. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a cross-sectional view of the LED light emitting devices of the example and the comparative example. [Figure 2] FIG. 2 is a diagram showing the emission spectra of the extracted light in the example and the comparative example. [Figure 3] FIG. 3 is a chromaticity diagram showing the chromaticity points (chromaticity coordinates) of the extracted light of the example and the comparative example in comparison with the blackbody radiation locus. DETAILED DESCRIPTION OF THE INVENTION

[0018] <1> LED element LED elements include laser diode elements. The emission peak wavelength of the LED element is not particularly limited, but is preferably within the range of 440 to 460 nm.

[0019] <2> 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 excited by the light emitted by the LED element. There are multiple combinations of one LED element and one or more phosphors that are excited by the light emitted by the LED element.

[0020] <3> phosphor Phosphors are substances that emit fluorescence when excited by the light emitted by the LED element. As described above, the phosphor preferably includes a green phosphor having an emission peak at 480 to 520 nm, a red phosphor having an emission peak at 640 to 680 nm, and a near-infrared phosphor having an emission peak at 780 to 820 nm. The green phosphor is Lu3Al5O 12 :Ce 3+ It is preferable that the composition be represented by the following formula: The red phosphor is CaAlSiN3:Eu 2+ It is preferable that the composition be represented by the following formula: The near-infrared phosphor is Li a Sr b La c Si d N e EU f (wherein a to f are numbers that satisfy a+b+c+d+e+f=100, 0≦a≦8.22, 0.22≦b≦17.33, 1.12≦c≦11.36, 22.41≦d≦38.09, 49.47≦e≦56.09, 0.88≦f≦1.01.)

[0021] <4> Continuous emission spectrum As described above, the light extracted from the light emitting device has a continuous emission spectrum in the range of 450 to 950 nm, and therefore can be suitably used as a measurement light source (light emitting device) for spectroscopic analysis devices and the like that require broadband performance. The term "continuous emission spectrum" means that the emission intensity of the emission spectrum is 0.05 or more (more preferably 0.1 or more) relative to the 800 nm standard over the entire range.

[0022] <5> Emission peak As described above, the extracted light has emission peaks at 770 to 820 nm and 550 to 650 nm, and it is preferable that the maximum emission peak intensity (B) at 550 to 650 nm is higher than the maximum emission peak intensity (A) at 770 to 820 nm. This makes it possible to suppress the near-infrared phosphor from causing the human eye to perceive red, thereby maintaining high color rendering properties. As mentioned above, the ratio (B / A) is preferably 1.03 to 1.55, which makes it possible to achieve both broadband characteristics (a continuous spectrum within the range of 450 to 950 nm) and high color rendering properties.

[0023] <6> chromaticity point As described above, it is preferable that the chromaticity point (chromaticity coordinates) of the extracted light be located below the blackbody radiation locus on the chromaticity diagram. The chromaticity diagram covers the visible light range (380 to 780 nm), and if the blackbody radiation locus is used as the reference, high color rendering properties cannot be maintained due to the influence of the red component contained in the near-infrared phosphor. Therefore, by positioning the chromaticity point of the extracted light below the blackbody radiation locus, it is possible to produce white light with high color rendering properties that takes the near-infrared phosphor into consideration. [Example]

[0024] 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.

[0025] 1, the LED light emitting device 1 of the embodiment includes a substrate 10, an LED element 2 bonded onto the substrate 10, and a first sealing material 3 that seals the LED element 2. The first sealing material 3 is made of a transparent resin 4 and a phosphor 5 dispersed in the resin 4.

[0026] The white light extracted from the LED light emitting device 1 of the embodiment has a continuous emission spectrum in the wavelength range of 450 to 950 nm, and has a color temperature in the range of 2500 to 5000 K, an average color rendering index Ra of 90 or more, and a special color rendering index R15 of 88 or more (preferably 90 or more). In contrast, the LED 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 LED light emitting devices of Examples 1 to 5 and Comparative Examples 1 to 3 shown in Table 1 were fabricated as follows, and the characteristics of the extracted light were measured.

[0027] [Table 1]

[0028] In Table 1, the LED element is a gallium nitride LED element manufactured by Toyoda Gosei Co., Ltd., which emits light with a peak wavelength of 440 to 460 nm. The resin used is silicone resin T-122 manufactured by Aica Kogyo Co., Ltd. BG802 / B2 is the product number of the green phosphor (LuAG) manufactured by Mitsubishi Chemical Corporation, and is Lu3Al5O 12 :Ce 3+ and has a peak wavelength in the range of 480 to 520 nm. C13P is the product number of a yellow phosphor (YAG) manufactured by Tokyo Chemical Industry Co., Ltd., and is Y3Al5O 12 :Ce 3+ and has a peak wavelength in the range of 530 to 570 nm. BR101N is the product number of a red phosphor (CASN) manufactured by Mitsubishi Chemical Corporation, and is CaAlSiN3:Eu 2+ and has a peak wavelength in the range of 630 to 670 nm. R660 is the product number of red phosphor (CASN) manufactured by Denka Co., Ltd., and is CaAlSiN3:Eu 2+ and has a peak wavelength in the range of 640 to 680 nm. NIR1 is the product number of a near-infrared phosphor manufactured by Daidensha, (Y, Lu, Gd) 3-x-y(Ga, Al, Sc)5O 12 :(Cr x , (Yb, Nd) y )(0.05 < x < 0.3, 0 ≦ y < 0.3) and has a peak wavelength at 690 - 730 nm. NIR2 is the product number of a near - infrared phosphor made by a major electronics company, has a composition represented by ScBO3:Cr, and has a peak wavelength at 790 - 830 nm. TIR800 is the product number of a near - infrared phosphor (sialon) developed by the National Institute for Materials Science (NIMS), Li a Sr b La c Si d N e Eu f (However, a - f are numbers that satisfy a + b + c + d + e + f = 100, 0 ≦ a ≦ 8.22, 0.22 ≦ b ≦ 17.33, 1.12 ≦ c ≦ 11.36, 22.41 ≦ d ≦ 38.09, 49.47 ≦ e ≦ 56.09, 0.88 ≦ f ≦ 1.01.) and has a peak wavelength at 780 - 820 nm.

[0029] (Manufacturing method) The LED element 2 was mounted on the substrate 10 to make it energizable. The phosphors shown in Table 1 were blended in the amount per 1 g of the resin, and mixed using a stirrer or the like to uniformly disperse the phosphors in the resin. This mixture of the resin and the phosphors was applied onto the LED element 2 using a dispenser or the like in the coating amount shown in Table 1. The resin was heat - cured in an oven to form the sealing material 3, and the LED light - emitting devices 1 of Examples 1 - 5 and Comparative Examples 1 - 3 were manufactured.

[0030] (Characteristics of the extracted light) The light emitted by the LED element 2 and the light emitted by the phosphor 5 during energization were used to extract the extracted light from each of the LED light - emitting devices 1 of Examples 1 - 5 and Comparative Examples 1 - 3. The measurement results of each extracted light are shown as follows. · Figure 2 shows the emission spectrum. Table 2 shows the maximum peak intensity (A) from 770 to 820 nm, the maximum peak intensity (B) from 550 to 650 nm, the ratio (B / A), the emission intensity at 800 nm (C), the emission intensity at 950 nm (D), the ratio (D / C), the correlated color temperature, the chromaticity coordinates on the chromaticity diagram, the special color rendering indexes R1 to R15, and the general color rendering index Ra. Figure 3 shows the chromaticity points (chromaticity coordinates) on the chromaticity diagram in comparison with the blackbody radiation locus.

[0031] [Table 2]

[0032] (summary) Comparative Example 1 has low emission intensity at 950 nm. This is thought to be due to the properties of the near-infrared phosphor. Also, Ra and R15 are low. This may be partly due to the chromaticity point being above the blackbody radiation locus. Comparative Example 2 has a wide bandwidth, but low Ra and R15, which may be partly due to the small ratio (B / A) of 0.92. Comparative Example 3 has broadband characteristics, and although Ra and R15 are higher than those of Comparative Examples 1 and 2, Ra does not reach 90 (it does not meet the performance of JIS Z9112:2019 high color rendering class 2). One reason for this may be that the x-coordinate and y-coordinate values ​​are almost on the blackbody radiation locus. In contrast to these, Examples 1 to 5 have broadband characteristics, and also have Ra of 90 or more and R15 of 88 or more (preferably 90 or more) in the color temperature range of 2500 to 5000 K, satisfying the performance of high color rendering (high color rendering class 2). Furthermore, Examples 1 to 5 also satisfy a special color rendering index R9 (red) of 65 or more.

[0033] The present invention is not limited to the above-described embodiments, and can be embodied by making appropriate modifications without departing from the spirit of the invention. [Explanation of symbols]

[0034] 1. Light-emitting device 2 LED elements 3. Encapsulating material 4. Resin 5. Phosphors 10 Substrate

Claims

1. An LED light emitting device comprising one or more LED elements and a plurality of phosphors, The light extracted from the LED light-emitting device has a continuous emission spectrum in the wavelength range of 450 to 950 nm, and has a color temperature in the range of 2500 to 5000 K, an average color rendering index Ra of 90 or more, and a special color rendering index R15 of 88 or more.

2. 2. The LED light-emitting device according to claim 1, wherein the extracted light has emission peaks at 770 to 820 nm and 550 to 650 nm, and the maximum emission peak intensity (B) at 550 to 650 nm is higher than the maximum emission peak intensity (A) at 770 to 820 nm.

3. 3. The LED light-emitting device according to claim 2, wherein the ratio (B / A) of the maximum emission peak intensity (B) in the range of 550 to 650 nm to the maximum emission peak intensity (A) in the range of 770 to 820 nm is 1.03 to 1.

55.

4. 2. The LED light-emitting device according to claim 1, wherein the chromaticity point of the extracted light in the chromaticity diagram of the CIE 1931 color system is located below the blackbody radiation locus.

5. An LED light emitting device comprising one or more LED elements and a plurality of phosphors, The LED element has an emission peak at 440 to 460 nm, the phosphors include a green phosphor having an emission peak in the range of 480 to 520 nm, a red phosphor having an emission peak in the range of 640 to 680 nm, and a near-infrared phosphor having an emission peak in the range of 780 to 820 nm; The green phosphor is Lu 3 Al 5 O 12 : Ce 3+ It has a composition represented by The red phosphor is CaAlSiN 3 :Eu 2+ It has a composition represented by The near-infrared phosphor is Li a Sr b La c Si d N e EU f (wherein a to f are numbers that satisfy a+b+c+d+e+f=100, 0≦a≦8.22, 0.22≦b≦17.33, 1.12≦c≦11.36, 22.41≦d≦38.09, 49.47≦e≦56.09, 0.88≦f≦1.01.)

6. A lighting fixture comprising the LED light-emitting device according to any one of claims 1 to 5.

7. A measurement light source comprising the LED light emitting device according to any one of claims 1 to 5.

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