Semiconductor light-emitting device

Abstract

The present invention addresses the problem of providing a semiconductor light emitting device in which chromaticity shift of white light due to the temperature inside the semiconductor light emitting device is suppressed. The problem is solved by a semiconductor light emitting device for emitting white light, the device comprising a substrate, a semiconductor light emitting element provided on the substrate and having an emission peak at wavelengths of 430 nm to 480 nm, and an optically transmissive material comprising a plurality of wavelength converting materials for converting the wavelength of light emitted from the semiconductor light emitting element, wherein, in the emission spectrum of the white light, the absolute value of a difference between the amount of change due to temperature in the emission spectrum at wavelengths greater than or equal to 500 nm and less than 605 nm and the amount of change due temperature in the emission spectrum at wavelengths greater than or equal to 605 nm and less than 650 nm is decreased.

Description

[Technical Field]

[0001] The present invention relates to a semiconductor light-emitting device comprising a semiconductor light-emitting element and a wavelength converting material. [Background technology]

[0002] 2. Description of the Related Art Semiconductor light emitting devices that emit white light by combining an LED (semiconductor light emitting element) and a phosphor have become widely used in a variety of applications due to their long life and low energy consumption.

[0003] In the field of general lighting, which is one of the application areas of semiconductor light-emitting devices, good color rendering properties are required in addition to low energy consumption. Patent Document 1 discloses a light-receiving and light-emitting medium including a broad-spectrum red phosphor and a narrow-spectrum red phosphor as a semiconductor light-emitting device that achieves both energy efficiency and color rendering properties. Furthermore, examples of narrow-band spectrum red phosphors include K2SiF6:Mn 4+ A fluoride fluorescent material represented by the following formula is known (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 8,921,875 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-209311 Summary of the Invention [Problem to be solved by the invention]

[0005] While further studying semiconductor light-emitting devices that can achieve both energy efficiency and color rendering properties using fluoride phosphors, the inventors discovered a new problem: that the chromaticity of white light emitted from a semiconductor light-emitting device varies depending on the temperature inside the semiconductor light-emitting device. An object of the present invention is to provide a semiconductor light-emitting device that suppresses the chromaticity deviation of white light that can occur in semiconductor light-emitting devices that use fluoride phosphors due to the temperature inside the semiconductor light-emitting device. [Means for solving the problem]

[0006] In order to solve the above problems, the inventors investigated changes in the light-emitting properties of wavelength converting materials due to temperature changes, and found that while fluoride phosphors have extremely high stability in the light-emitting properties due to temperature changes, some other wavelength converting materials have significantly different light-emitting properties due to temperature changes. Furthermore, when the spectrum of white light emitted by a semiconductor light-emitting device containing a fluoride phosphor as a wavelength converting material was investigated, they came to the conclusion that there exists a wavelength range in which the light-emitting properties change significantly due to temperature changes. Based on these findings, the researchers conducted extensive research and completed a semiconductor light-emitting device that suppresses deviations in the chromaticity of white light due to temperature changes within the device.

[0007] The present invention includes the following aspects. [1] a base body; a semiconductor light-emitting element provided on the substrate and having an emission peak at a wavelength of 430 nm to 480 nm; a transparent material including a plurality of wavelength converting materials that convert the wavelength of light emitted from the semiconductor light emitting element, In the emission spectrum of the white light, The first region is wavelengths of 380 nm or more and less than 500 nm, The second region is wavelengths of 500 nm or more and less than 605 nm. The third region is wavelengths between 605 nm and 650 nm. The wavelength range of 650 nm to 780 nm is defined as the fourth region, the wavelength converting material includes at least a phosphor A having an emission peak in the second region, a fluoride phosphor having an emission peak in the third region, and a phosphor B having an emission peak in a wavelength region of 590 nm or more and 780 nm or less; a change in the integral value of the spectral radiant flux of the white light in the second region when the operating temperature of the semiconductor light emitting device is changed from 25°C to 85°C is ΔS2 (%); When the operating temperature of the semiconductor light emitting device is changed from 25°C to 85°C, the change in the integral value of the spectral radiant flux of the white light in the third region is ΔS3 (%). When the color temperature of the white light is 3000 K or less, the value of |ΔS2-ΔS3| is 8% or less, When the color temperature of the white light is in a range higher than 3000 K, the value of |ΔS2-ΔS3| is 12% or less. Semiconductor light-emitting device. [2] a base; a semiconductor light-emitting element provided on the substrate and having an emission peak at a wavelength of 430 nm to 480 nm; a transparent material including a plurality of wavelength converting materials that convert the wavelength of light emitted from the semiconductor light emitting element, the wavelength converting material includes at least a phosphor A having an emission peak in a wavelength range of 500 nm or more and less than 605 nm, a fluoride phosphor having an emission peak in a wavelength range of 605 nm or more and less than 650 nm, and a phosphor B having an emission peak in a wavelength range of 590 nm or more and less than 780 nm, The phosphor A and the phosphor B each have a change (%) of 8% or more in the integrated value of the spectral radiant flux of the fluorescence emitted from the phosphor when the operating temperature is changed from 25°C to 85°C, When the operating temperature of the semiconductor light emitting device is changed from 25°C to 85°C, the amount of change in chromaticity of the white light on the chromaticity diagram is within 3 steps of the MacAdam ellipse. Semiconductor light-emitting device. [3] In the emission spectrum of the white light, the integral value of the spectral radiant flux in the wavelength region of 380 nm or more and 780 nm or less is defined as S, and the integral value of the spectral radiant flux in the fourth region is defined as S A When S A The semiconductor light emitting device according to [1] or [2], wherein the value of / S is 0.06 or more and 0.15 or less. [4] The semiconductor light emitting device according to any one of [1] to [3], wherein the phosphor A is a garnet phosphor. [5] The semiconductor light emitting device according to any one of [1] to [4], wherein the phosphor A is a LuAG phosphor. [6] The semiconductor light emitting device according to any one of [1] to [5], wherein the phosphor B is a SCASN phosphor. [7] The semiconductor light emitting device according to any one of [1] to [6], wherein the fluoride phosphor is a KSF phosphor. [8] The semiconductor light emitting device according to any one of [1] to [7], wherein the white light has a color rendering index Ra of 90 or more. [9] The semiconductor light emitting device according to any one of [1] to [8], wherein the amount of the fluoride phosphor mixed in the translucent material relative to the weight of the translucent material is 35 wt % or less.

[10] The semiconductor light emitting device according to any one of [1] to [9], wherein the phosphor B has a peak wavelength of 620 nm or more. [Effects of the Invention]

[0008] The present invention can provide a semiconductor light emitting device that suppresses deviation in chromaticity of white light due to temperature inside the semiconductor light emitting device. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a graph showing the emission spectrum at room temperature (25° C., solid line) and the emission spectrum at high temperature (85° C., dashed line) of the LuAG phosphor used in the examples. [Figure 2] 1 is a graph showing the emission spectrum at room temperature (25° C., solid line) and the emission spectrum at high temperature (85° C., dashed line) of the YAG phosphor used in the examples. [Figure 3] 1 is a graph showing the emission spectrum at room temperature (25° C., solid line) and the emission spectrum at high temperature (85° C., dashed line) of the KSF phosphor used in the examples. [Figure 4]1 is a graph showing the emission spectrum at room temperature (25° C., solid line) and the emission spectrum at high temperature (85° C., dashed line) of the SCASN phosphor used in the examples. [Figure 5] 1 is a graph showing the emission spectrum at room temperature (25° C., solid line) and the emission spectrum at high temperature (85° C., dashed line) of the SCASN phosphor used in the examples. [Figure 6] 1 is a graph (corresponding to an example) showing the emission spectrum at room temperature (25° C., solid line) and the emission spectrum at high temperature (85° C., dashed line) of the white light emitting device 1 used in the example. [Figure 7] 1 is a graph (corresponding to a comparative example) showing the emission spectrum at room temperature (25° C., solid line) and the emission spectrum at a high temperature (85° C., dashed line) of the white light emitting device 8 used in the example. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in more detail below, but the scope of the invention is not limited to specific embodiments. Furthermore, in this specification, a numerical range represented by "X to Y" means a numerical range including X as the lower limit and Y as the upper limit. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined in any combination.

[0011] One aspect of the present invention is a semiconductor light-emitting device that emits white light, comprising: a base; a semiconductor light-emitting element provided on the base and having an emission peak in a wavelength range of 430 nm to 480 nm; and a light-transmitting material that includes a plurality of wavelength conversion materials that convert the wavelength of light emitted from the semiconductor light-emitting element.

[0012] The base may be any substrate capable of arranging a semiconductor light-emitting element, typically a plate-shaped substrate, but is not particularly limited thereto. One or more semiconductor light-emitting elements are arranged on the base, and a plurality of semiconductor light-emitting elements may be arranged in an array or in a plane. The semiconductor light-emitting element arranged on the base is connected to a power source and is ready to emit a predetermined light. The semiconductor light emitting element disposed on the base is sealed with a light-transmitting material containing a plurality of wavelength converting materials that convert the wavelength of light emitted from the semiconductor light emitting element. With this configuration, the wavelength of part of the light emitted from the semiconductor light emitting element is converted by the wavelength converting materials dispersed in the light-transmitting material, and the light becomes light with a wavelength different from that of the semiconductor light emitting element.

[0013] The semiconductor light emitting element is a blue semiconductor light emitting element having an emission peak at a wavelength of 430 nm to 480 nm. A semiconductor light emitting element other than the blue semiconductor light emitting element, for example, a green semiconductor light emitting element or a red semiconductor light emitting element may be used in combination.

[0014] The light-transmitting material functions as a wavelength conversion member by including a plurality of wavelength conversion materials that convert the wavelength of light emitted from the semiconductor light-emitting element. As the light-transmitting material, a light-transmitting resin can be used, and typically, a silicone resin or an epoxy resin is used. Furthermore, the wavelength conversion material included in the light-transmitting material is typically a phosphor.

[0015] In this embodiment, the semiconductor light emitting device emits white light. When the wavelength of the emission spectrum is defined as a first region equal to or greater than 380 nm and less than 500 nm, a second region equal to or greater than 500 nm and less than 605 nm, a third region equal to or greater than 605 nm and less than 650 nm, and a fourth region equal to or greater than 650 nm and less than 780 nm, the emitted white light contains phosphor A having an emission peak in the second region, a fluoride phosphor having an emission peak in the third region, and phosphor B having an emission peak in a wavelength region equal to or greater than 590 nm and less than 780 nm.

[0016] Phosphor A is a phosphor having an emission peak in the second region, i.e., a wavelength region of 500 nm or more and less than 605 nm. Phosphor A is preferably a green phosphor that emits fluorescence in the green wavelength region. Phosphors other than green phosphors that have an emission peak in the second region, such as a yellow phosphor that emits fluorescence in the yellow wavelength region or an orange phosphor that emits fluorescence in the orange wavelength region, may also be used.

[0017] An example of a green phosphor is Ce 3+ Aluminate activated by Eu 2+ Activated alkaline earth silicate, Eu 2+ Activated alkaline earth silicon nitride, Ce 3+ Examples of such green phosphors include those based on silicon nitride and activator. Among these, garnet phosphors having a garnet structure, such as YAG and LuAG, are preferred, and LuAG phosphors represented by the following general formula (I) are preferred. Lu a (Ce,Tb,Y) b (Ga,Sc) c Al d O e (I) In the general formula (I), a, b, c, d, and e satisfy the relationships a+b=3, 0≦b≦0.2, 4.5≦c+d≦5.5, 0≦c≦2.6, and 10.8≦e≦13.4.

[0018] The fluoride phosphor is a phosphor that has an emission peak in the third region, that is, in the wavelength region of 605 nm or more and less than 650 nm. 4+ as an activator and an alkali metal fluoro complex as the host crystal. 2+x M y Mn z F n (A is Na and / or K; M is Si and Al; -1≦x≦1 and 0.9≦y+z≦1.1 and 0.001≦z≦0.4 and 5≦n≦7). Specific examples include K2SiF6:Mn (referred to as KSF phosphor) and Na2SiF6:Mn, and the KSF phosphor is preferred.

[0019] Fluoride phosphors have a small half-width of their fluorescence spectrum, which is usually 1 nm or more, and may be 2 nm or more, and is usually 15 nm or less, and may be 10 nm or less.

[0020] Phosphor B is a phosphor having an emission peak in the wavelength region of 590 nm or more and 780 nm or less. Phosphor B is preferably a red phosphor that emits fluorescence in the red wavelength region. Phosphors other than red phosphors, such as orange phosphors that emit fluorescence in the orange wavelength region, may also be used.

[0021] Examples of red to orange phosphors include Eu 2+ Examples of phosphors include those using as an activator a phosphor having a crystal matrix made of alkaline earth silicon nitride, α-sialon, or alkaline earth silicate. Of these, the SCASN phosphor represented by the following general formula (II) is preferred. (Ca,Sr,Ba)AlSiN3:Eu...(II)

[0022] Alternatively, a blue phosphor having an emission peak in the first region, that is, in the wavelength region of 380 nm or more and less than 500 nm, may be used as the phosphor.

[0023] The amount of phosphor in the translucent material is not particularly limited and can be appropriately determined by a person skilled in the art so that white light having a desired color temperature is emitted. However, in this embodiment, the amount of fluoride phosphor is preferably 35 wt% or less, more preferably 30 wt% or less, based on the weight of the translucent material. While there is no lower limit, it is typically 5 wt% or more, and may be 10 wt% or more. Fluoride phosphors have excellent stability in their emission characteristics with temperature. Therefore, in a light-emitting device containing a fluoride phosphor, if other phosphors exhibit relatively large temperature-dependent changes in emission characteristics and are incorporated in large amounts, temperature-dependent chromaticity shifts in the white light are likely to occur. This embodiment, which can suppress temperature-dependent chromaticity shifts, is preferably applied when the amount of fluoride phosphor incorporated is within the above range.

[0024] The light-emitting device of this embodiment emits white light. The white light may be incandescent white light, warm white light, or daylight white light, and its color temperature is not particularly limited. It is usually 1600K or higher, may be 2000K or higher, or may be 2400K or higher. It is also usually 12000K or lower, may be 7000K or lower, or may be 6500K or lower.

[0025] The light-emitting device of this embodiment is a light-emitting device in which temperature-dependent chromaticity shift of white light is suppressed. The inventors confirmed changes in the emission characteristics of wavelength conversion materials due to temperature changes and found that fluoride phosphors have extremely high stability of emission characteristics due to temperature changes. Furthermore, when the emission spectrum of white light emitted from a semiconductor light-emitting device containing a fluoride phosphor as a wavelength conversion material was confirmed, it was found that there is a wavelength region in which the emission characteristics change significantly with temperature changes. The inventors then found that temperature-dependent chromaticity shift of white light is suppressed by reducing the absolute value of the difference between the temperature-dependent change in the emission spectrum in the second region and the temperature-dependent change in the emission spectrum in the third region in the emission spectrum of white light emitted from the light-emitting device.

[0026] That is, when the change in the integral value of the spectral radiant flux of the white light in the second region when the operating temperature of the semiconductor light-emitting device is changed from 25°C to 85°C is ΔS2 (%), and the change in the integral value of the spectral radiant flux of the white light in the third region when the operating temperature of the semiconductor light-emitting device is changed from 25°C to 85°C is ΔS3 (%), the chromaticity shift of the white light due to temperature change is suppressed when the value of |ΔS2-ΔS3| is 8% or less when the color temperature of the white light is 3000K or less, and when the value of |ΔS2-ΔS3| is 12% or less when the color temperature of the white light is in the range higher than 3000K.

[0027] When the color temperature of the white light is 3000K or less, i.e., when it is incandescent white light, the change in the emission spectrum in the second and third regions due to temperature has a relatively large effect on chromaticity deviation, so the absolute value of the difference must be 8% or less.When the color temperature of the white light is greater than 3000K, i.e., when it is warm white or daylight white light, the change in the emission spectrum in the second and third regions due to temperature has a relatively small effect on chromaticity deviation, so the absolute value of the difference must be 12% or less.

[0028] In the semiconductor light emitting device of this embodiment, the integral value of the spectral radiant flux in the wavelength region of 380 nm or more and 780 nm or less in the emission spectrum of white light is defined as S, and the integral value of the spectral radiant flux in the fourth region is defined as S A Then, S A It is preferable that the value of / S is 0.06 or more and 0.15 or less. When the integrated value of the emission spectrum of the fourth region, i.e., the red region, is in the above range, it is possible to suppress chromaticity deviation while improving the color rendering of white light. In this embodiment, the color rendering evaluation index Ra of the white light emitted from the semiconductor light emitting device is preferably 90 or more, and more preferably 95 or more.

[0029] As described above, in the emission spectrum of white light from the semiconductor light emitting device, the absolute value of the difference between the amount of change in the emission spectrum with temperature in the second region and the amount of change in the emission spectrum with temperature in the third region is reduced, thereby suppressing chromaticity deviation of the white light due to temperature changes. Specifically, when the operating temperature of the semiconductor light emitting device is changed from 25°C to 85°C, the amount of change in chromaticity on the chromaticity diagram of the white light can be kept within 3 steps of the MacAdam ellipse, preferably within 2 steps.

[0030] The MacAdam ellipse, which is used in, for example, Japanese Patent Application Laid-Open Nos. 2020-198345 and 2019-125582, indicates the range on the CIExy chromaticity diagram in which a person with normal color vision cannot distinguish between colors based on the results of color matching experiments, and is an ellipse that represents the standard deviation of discrimination variation for a specific center color on the CIExy chromaticity diagram. In this embodiment, the chromaticity deviation due to the temperature of white light was determined using the following criteria.

[0031] <Definition of criteria> On the CIE chromaticity coordinates, the distances from the center of the MacAdam ellipse corresponding to each step are defined as Cx and Cy for the x and y coordinates, respectively. The square root of the sum of the products of Cx and Cy is defined as the maximum value for each step range. Under this definition, when the operating temperature of a light-emitting device is changed from 25°C to 85°C, the change in chromaticity is preferably within 3 steps, and more preferably within 2 steps.

[0032] As described above, in order to obtain a semiconductor light-emitting device in which the amount of chromaticity change on the chromaticity diagram of white light when the operating temperature of the semiconductor light-emitting device is changed from 25°C to 85°C is within 3 steps of the MacAdam ellipse, it was conceived that this can be easily achieved by using a constant amount of phosphor A and phosphor B, each of which will change (%) in the integrated value of the spectral radiant flux of the fluorescence emitted from the phosphor when the operating temperature is changed from 25°C to 85°C.

[0033] That is, another aspect of the present invention is a semiconductor light emitting device that emits white light, comprising: a base; a semiconductor light emitting element provided on the base and having an emission peak in a wavelength range of 430 nm to 480 nm; and a light-transmitting material containing a plurality of wavelength converting materials that convert the wavelength of light emitted from the semiconductor light emitting element, the wavelength converting material includes at least a phosphor A having an emission peak in a wavelength range of 500 nm or more and less than 605 nm, a fluoride phosphor having an emission peak in a wavelength range of 605 nm or more and less than 650 nm, and a phosphor B having an emission peak in a wavelength range of 590 nm or more and less than 780 nm, In the emission spectrum of the white light, The first region is wavelengths of 380 nm or more and less than 500 nm, The second region is wavelengths of 500 nm or more and less than 605 nm. The third region is wavelengths between 605 nm and 650 nm. The wavelength range of 650 nm to 780 nm is defined as the fourth region, the wavelength converting material includes at least a phosphor A having an emission peak in the second region, a fluoride phosphor having an emission peak in the third region, and a phosphor B having an emission peak in a wavelength region of 590 nm or more and 780 nm or less; The change in the integral value of the spectral radiant flux of the fluorescence emitted by the phosphor A when the operating temperature of the phosphor A is changed from 25°C to 85°C is defined as ΔSelmtA (%), When the operating temperature of the phosphor B is changed from 25°C to 85°C, the change in the integral value of the spectral radiant flux of the fluorescence emitted by the phosphor B is ΔSelmtB (%), The phosphor A has a ΔSelmt A (%) is 8% or more, The phosphor B has a ΔSelmt B (%) is 8% or more, The semiconductor light emitting device is one in which the amount of change in chromaticity of the white light on the chromaticity diagram when the operating temperature of the semiconductor light emitting device is changed from 25°C to 85°C is within 3 steps of the MacAdam ellipse.

[0034] The change amount ΔSelmt A (%) is more preferably 8% or more and 20% or less, and even more preferably 8% or more and 15% or less, and the change amount ΔSelmt B (%) is more preferably 8% or more and 20% or less, and even more preferably 8% or more and 15% or less.

[0035] In another aspect of the present invention, the semiconductor light emitting device can be identified based on the change in the light emitting characteristics of the phosphor due to a change in temperature. That is, a semiconductor light emitting device that emits white light includes a base, a semiconductor light emitting element that is provided on the base and has an emission peak at a wavelength of 430 nm to 480 nm, and a light-transmitting material that includes a plurality of wavelength converting materials that convert the wavelength of light emitted from the semiconductor light emitting element, In the emission spectrum of the white light, The first region is wavelengths of 380 nm or more and less than 500 nm, The second region is wavelengths of 500 nm or more and less than 605 nm. The third region is wavelengths between 605 nm and 650 nm. The wavelength range of 650 nm to 780 nm is defined as the fourth region, the wavelength converting material includes at least a phosphor A having an emission peak in the second region, a fluoride phosphor having an emission peak in the third region, and a phosphor B having an emission peak in a wavelength region of 590 nm or more and 780 nm or less; The amount of change in the integral value of the spectral radiant flux of the fluorescence emitted by the phosphor A when the operating temperature of the phosphor A is changed from 25°C to 85°C is defined as ΔSelmt A (%)year, The amount of change in the integral value of the spectral radiant flux of the fluorescence emitted by the phosphor B when the operating temperature of the phosphor B is changed from 25°C to 85°C is defined as ΔSelmt B When set to (%), When the color temperature of the white light is 3000K or less, |ΔSelmt A -ΔSelmt B the value of | is 6% or less, In the range where the color temperature of the white light is higher than 3000K, |ΔSelmt A -ΔSelmt B The semiconductor light emitting device has a value of | 7% or less.

[0036] Furthermore, in yet another aspect of the present invention, it is possible to provide a method for designing a semiconductor light emitting device that suppresses deviation in chromaticity of white light due to temperature inside the semiconductor light emitting device. That is, a substrate and a semiconductor light-emitting element provided on the substrate and having an emission peak at a wavelength of 430 nm to 480 nm; a light-transmitting material including a plurality of wavelength conversion materials that convert the wavelength of light emitted from the semiconductor light-emitting element, In the emission spectrum of the white light, The first region is wavelengths of 380 nm or more and less than 500 nm, The second region is wavelengths of 500 nm or more and less than 605 nm. The third region is wavelengths between 605 nm and 650 nm. The wavelength range of 650 nm to 780 nm is defined as the fourth region, the wavelength converting material includes at least a phosphor A having an emission peak in the second region, a fluoride phosphor having an emission peak in the third region, and a phosphor B having an emission peak in a wavelength region of 590 nm or more and 780 nm or less; a change in the integral value of the spectral radiant flux of the white light in the second region when the operating temperature of the semiconductor light emitting device is changed from 25°C to 85°C is ΔS2 (%); When the operating temperature of the semiconductor light emitting device is changed from 25°C to 85°C, the change in the integral value of the spectral radiant flux of the white light in the third region is ΔS3 (%). When the color temperature of the white light is 3000 K or less, the value of |ΔS2-ΔS3| is 8% or less, This is a method for designing a semiconductor light emitting device, in which the wavelength converting material is adjusted so that the value of |ΔS2−ΔS3| is 12% or less when the color temperature of the white light is in a range higher than 3000K.

[0037] In the above-described method for designing a semiconductor light-emitting device, the wavelength conversion material can be adjusted mainly by selecting phosphor A and phosphor B. Specifically, the amount of change in the integral value of the spectral radiant flux of the fluorescence emitted by phosphor A when the operating temperature of phosphor A is changed from 25°C to 85°C is defined as ΔSelmt A (%), and the amount of change in the integral value of the spectral radiant flux of the fluorescence emitted by the phosphor B when the operating temperature of the phosphor B is changed from 25°C to 85°C is ΔSelmt B (%), ΔSelmt A It is preferable to use phosphor A having a value of 8% or more and 20% or less, and ΔSelmtB It is preferable to use phosphor B having a content of 8% or more and 20% or less. A -ΔSelmt B It is preferable to use phosphors A and B in which the value of |ΔSelmt | is 6% or less, and in the range in which the color temperature of the white light is higher than 3000 K, A -ΔSelmt B It is preferable to use phosphors A and B such that the value of | is 7% or less.

[0038] The semiconductor light emitting device according to this embodiment emits white light and is suitable for general lighting because chromaticity deviation due to operating temperature is suppressed, but may also be used for other purposes. [Example]

[0039] <Example> White light emitting devices 1 to 9 (COB: chip-on-board type) were fabricated as shown in Table 1, and various data were obtained while the operating temperature was changed from 25°C to 85°C. Note that the weight (wt%) of KSF in Table 1 is the weight relative to the total amount of translucent material excluding phosphor. Specifically, the device was fabricated by placing a blue semiconductor light-emitting element (emission peak wavelength: approximately 450 nm) on a substrate, and then placing a translucent material (silicone resin) containing the phosphor shown in Table 1 on top of that. Note that the chromaticity change in Table 1 indicates the MacAdam ellipse size within which the chromaticity change occurs when the operating temperature is changed from 25°C to 85°C. The emission wavelengths of the phosphors used in the examples are as follows: LuAG: Solid line in Figure 1 YAG: Solid line in Figure 2 KSF: Solid line in Figure 3 SCASN: Solid line in Figure 4 or solid line in Figure 5

[0040] [Table 1]

[0041] The results of the examples show that when the chromaticity deviation of the white light emitted from the light-emitting device relative to the operating temperature is small, the difference in intensity change between the second and third regions is small, i.e., the value of |ΔS2-ΔS3| is small. Furthermore, it was found that as the color temperature increases, the range of the value of |ΔS2-ΔS3| when the chromaticity deviation falls within the preferable range also increases. The temperature changes in the emission spectra of white light-emitting device 1 and white light-emitting device 8 are shown in Figures 6 and 7. As can be seen from Figure 6, the semiconductor light-emitting device with small chromaticity shifts due to temperature has a large amount of spectral change in the second region, but also a large amount of spectral change in the third region, and the difference in intensity change between the two regions is small. On the other hand, as can be seen from Figure 7, the semiconductor light-emitting device with large chromaticity shifts due to temperature has a large amount of spectral change in the second region, but a small amount of spectral change in the third region, and the difference in intensity change between the two regions is large.

[0042] This time, we used YAG and LuAG as phosphors with emission peaks in the second region. These phosphors are widely used in semiconductor light-emitting devices. Analysis of the results showed that samples using LuAG tended to have smaller chromaticity shifts due to operating temperature than samples using YAG. The characteristics of YAG and LuAG were confirmed, and the difference in the amount of change in emission intensity in the second region due to operating temperature was confirmed. The amount of change in emission intensity in the second region was 14.9% and 11.9% for YAG and LuAG, respectively. In relation to the small change in emission intensity in the third region due to operating temperature, which is derived from fluoride phosphors, it is better for the amount of change in emission intensity in the second region to be small. Therefore, it can be assumed that the chromaticity deviation of the light-emitting device will be reduced more when LuAG is used than when YAG is used.

[0043] Using fluoride phosphors and SCASN as phosphors with emission peaks in the wavelength range of 590nm to 780nm, we investigated the relationship between chromaticity shift due to temperature changes in light-emitting devices and SCASN.When using SCASN with a peak wavelength of 620nm or more and SCASN with a peak wavelength of less than 620nm, we found that the one using SCASN with a longer peak wavelength showed a more favorable tendency, with smaller chromaticity shift in white light. The decrease in emission intensity with operating temperature is greater for SCASN than for fluoride phosphors, and the decrease in emission intensity due to temperature changes is particularly large for SCASN around the emission peak wavelength. Because fluoride phosphors have sharp emission spectra, if the decrease in emission intensity is large in the region overlapping with the emission region of fluoride phosphors and in the longer wavelength region, the decrease is balanced in the spectrum of the light-emitting device as a whole, reducing chromaticity deviation.

Claims

1. a substrate; a semiconductor light-emitting element provided on the substrate and having an emission peak at a wavelength of 430 nm to 480 nm; a transparent material including a plurality of wavelength converting materials that convert the wavelength of light emitted from the semiconductor light emitting element, The color rendering index Ra of the white light is 90 or more, In the emission spectrum of the white light, A first region is a wavelength of 380 nm or more and less than 500 nm, A wavelength of 500 nm or more and less than 605 nm is a second region; A third region is a wavelength of 605 nm or more and less than 650 nm. A wavelength of 650 nm or more and 780 nm or less is defined as a fourth region, the wavelength converting material includes at least a phosphor A which is an LuAG phosphor having an emission peak in the second region, a fluoride phosphor having an emission peak in the third region, and a phosphor B having an emission peak in a wavelength region of 590 nm or more and 780 nm or less; a change in the integral value of the spectral radiant flux of the white light in the second region when the operating temperature of the semiconductor light emitting device is changed from 25°C to 85°C, where the integral value at an operating temperature of 25°C is set to 100%, is defined as ΔS2 (%); When the operating temperature of the semiconductor light emitting device is changed from 25°C to 85°C, the amount of change in the integral value of the spectral radiant flux of the white light in the third region when the integral value at an operating temperature of 25°C is set to 100% is defined as ΔS3 (%). When the color temperature of the white light is 3000 K or less, the value of |ΔS2−ΔS3| is 8% or less, When the color temperature of the white light is in a range higher than 3000 K, the value of |ΔS2−ΔS3| is 12% or less, In the emission spectrum of the white light, when an integral value of the spectral radiant flux in a wavelength region of 380 nm or more and 780 nm or less is S and an integral value of the spectral radiant flux in the fourth region is SA, The SA / S value is 0.06 or more and 0.15 or less, The phosphor B is a SCASN phosphor having a peak wavelength of 620 nm or more. Semiconductor light-emitting device.

2. a substrate; a semiconductor light-emitting element provided on the substrate and having an emission peak at a wavelength of 430 nm to 480 nm; a transparent material including a plurality of wavelength converting materials that convert the wavelength of light emitted from the semiconductor light emitting element, The color rendering index Ra of the white light is 90 or more, the wavelength converting material includes at least a phosphor A which is an LuAG phosphor having an emission peak in a wavelength range of 500 nm or more and less than 605 nm, a fluoride phosphor having an emission peak in a wavelength range of 605 nm or more and less than 650 nm, and a phosphor B having an emission peak in a wavelength range of 590 nm or more and 780 nm or less; For each of the phosphors A and B, when the operating temperature is changed from 25°C to 85°C, the integral value of the spectral radiant flux of the fluorescence emitted from the phosphors changes by 8% or more, assuming that the integral value at an operating temperature of 25°C is 100%; the amount of change in chromaticity of the white light on the chromaticity diagram when the operating temperature of the semiconductor light emitting device is changed from 25°C to 85°C is within 3 steps of a MacAdam ellipse; In the emission spectrum of the white light, when an integral value of the spectral radiant flux in a wavelength region of 380 nm or more and 780 nm or less is S and an integral value of the spectral radiant flux in the fourth region is SA, The SA / S value is 0.06 or more and 0.15 or less, The phosphor B is a SCASN phosphor having a peak wavelength of 620 nm or more. Semiconductor light-emitting device.

3. 3. The semiconductor light emitting device according to claim 1, wherein the fluoride phosphor is a KSF phosphor.

4. 3. The semiconductor light emitting device according to claim 1, wherein the amount of said fluoride phosphor mixed in said light transmitting material is 35 wt % or less with respect to the weight of said light transmitting material.

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