Light-emitting device and lighting fixture

Abstract

This light-emitting device comprises: a light-emitting element that emits light having a main wavelength in the range from 400 nm to 490 nm; and a phosphor that emits light by being excited by the light emitted by the light-emitting element. In the emission spectrum of the light-emitting device, a first integrated value of emission intensities in the wavelength range from 600 nm to 780 nm is less than 22.5% of a second integrated value of emission intensities in the wavelength range from 380 nm to 780 nm, and a third integrated value of emission intensities in the wavelength range from 640 nm to 780 nm is less than 7.0% of the second integrated value.

Description

Light-emitting devices and luminaires

[0001] This disclosure relates to light-emitting devices and luminaires.

[0002] It is known that europium-doped alkaline earth metal silicon nitride or europium-doped alkaline earth metal oxynitride is used as the phosphor in light-emitting devices (for example, Patent Document 1).

[0003] Special Publication No. 2015-529701

[0004] Light-emitting devices require a high luminous flux.

[0005] The purpose of this disclosure is to provide a light-emitting device and a luminaire capable of increasing luminous flux.

[0006] According to embodiments of the present disclosure, the light-emitting device comprises a light-emitting element that emits light having a dominant wavelength in the range of 400 nm to 490 nm, and a phosphor that is excited by the light emitted by the light-emitting element and emits light, wherein in the emission spectrum of the light-emitting device, the first integral value of the emission intensity in the wavelength range of 600 nm to 780 nm is less than 22.5% of the second integral value of the emission intensity in the wavelength range of 380 nm to 780 nm, and the third integral value of the emission intensity in the wavelength range of 640 nm to 780 nm is less than 7.0% of the second integral value.

[0007] According to this disclosure, the luminous flux can be increased.

[0008] This figure shows the light spectrum and luminous efficiency curve of the light emitted by the light-emitting device. This is a plan view showing Example 1 of the light-emitting device according to the first embodiment. This is a cross-sectional view taken along line III-III in Figure 1. This is a cross-sectional view showing Example 2 of the light-emitting device according to the first embodiment. This is an enlarged view of area V in Figure 4. This is a cross-sectional view of the luminaire according to the second embodiment. This figure shows the emission spectrum and luminous efficiency curve of Example 1, Example 2, Comparative Example 1 and Comparative Example 2. This figure shows the emission spectrum and luminous efficiency curve of Example 3, Comparative Example 1, Comparative Example 2 and Reference Example 1. This figure shows the emission spectrum and luminous efficiency curve of Example 4, Example 5, Comparative Example 1 and Reference Example 3. This figure shows the emission spectrum and luminous efficiency curve of Example 6, Comparative Example 1 and Reference Example 2. This figure shows the emission spectrum and luminous efficiency curve of Example 2, Example 5 and Examples 7 to 9. This figure shows the emission spectrum and luminous efficiency curve of Comparative Example 3 and Examples 10 to 13. This figure shows the xy chromaticity coordinates of the light emitted by the phosphor.

[0009] The embodiments for implementing this disclosure will be described in detail below with reference to the drawings. The embodiments described below are examples for realizing the technical concept of the invention and do not limit this disclosure to the configurations and numerical values ​​described. In each drawing, the same reference numerals are used for the same components, and redundant explanations may be omitted as appropriate. The size, positional relationships, etc., of each component shown in each drawing may be exaggerated to facilitate understanding of the invention. Furthermore, end view diagrams showing cross-sections may be used as cross-sectional views.

[0010] (First Embodiment) The luminous flux of the light-emitting device is obtained by multiplying the radiant flux of the light emitted by the light-emitting device for each wavelength by the relative luminous efficiency for each wavelength and integrating it with respect to wavelength. As the relative luminous efficiency, the photopic standard relative luminous efficiency is used. The photopic standard relative luminous efficiency is the luminous efficiency in bright light, and is maximum at a wavelength of 555 nm. The more wavelengths in the spectrum of light emitted by the light-emitting device that have high sensitivity on the luminous efficiency curve are included, the higher the luminous flux.

[0011] Figure 1 shows the spectrum of light emitted by the light-emitting device and the relative luminous efficiency curve. The horizontal axis represents the wavelength of light, showing the wavelength range from 380 nm to 780 nm. The vertical axis corresponds to the emission intensity of the light emitted by the light-emitting device, and is in arbitrary units (a.u.) with the maximum emission intensity of Comparative Example 1 set to 100. As shown in Figure 1, the relative luminous efficiency is maximum at a wavelength of 555 nm and decreases at wavelengths of 600 nm and above. In particular, the relative luminous efficiency decreases significantly at wavelengths of 640 nm and above.

[0012] Example 1 and Comparative Example 1 are emission spectra of a light-emitting device having a light-emitting element and a phosphor, as described later. In Example 1 and Comparative Example 1, the peaks with wavelengths less than 470 nm are mainly emission spectra of the light-emitting element that excites the phosphor. The emission spectra with wavelengths of 470 nm or more are mainly spectra of light emitted by the phosphor excited by the light-emitting element. The range from 380 nm to 780 nm is defined as wavelength range 50, the range from 600 nm to 780 nm as wavelength range 51, the range from 640 nm to 780 nm as wavelength range 52, and the range from 470 nm to 520 nm as wavelength range 53.

[0013] The second integrated value 50A of the emission intensity in wavelength range 50 is the value obtained by integrating the emission intensity from wavelengths of 380 nm to 780 nm. The first integrated value 51A of the emission intensity in wavelength range 51 is the value obtained by integrating the emission intensity from wavelengths of 600 nm to 780 nm. The third integrated value 52A of the emission intensity in wavelength range 52 is the value obtained by integrating the emission intensity from wavelengths of 640 nm to 780 nm. The fourth integrated value 53A of the emission intensity in wavelength range 53 is the value obtained by integrating the emission intensity from wavelengths of 470 nm to 520 nm. In Figure 1, the areas corresponding to the first integrated value 51A, the third integrated value 52A, and the fourth integrated value 53A in Example 1 are shown by hatching.

[0014] In Example 1, the first integral value 51A and the third integral value 52A are smaller than those in Comparative Example 1. As a result, the emission spectrum of Example 1 has more wavelength components with high luminosity compared to the emission spectrum of Comparative Example 1. Consequently, the luminous flux of the light-emitting device in Example 1 is expected to be higher than that of the light-emitting device in Comparative Example 1. In the first embodiment, the ratio of the first integral value 51A to the second integral value 50A, the ratio of the third integral value 52A to the second integral value 50A, and the ratio of the first integral value 51A to the fourth integral value 53A are used as indicators of the phosphor.

[0015] The first embodiment will be described below.

[0016] (Example 1 of a light-emitting device) The first embodiment will be described below. Figure 2 is a plan view showing Example 1 of a light-emitting device according to the first embodiment. Figure 3 is a cross-sectional view taken along line III-III in Figure 1. The sealing member 22 is not shown in Figure 2.

[0017] As shown in Figures 2 and 3, the light-emitting device 100 comprises a package 10, a light-emitting element 16, and a protective element 17. The package 10 has a base body 12, lead terminals 18A and 18B, and a sealing member 22. The base body 12 has a recess 11. The lead terminals 18A and 18B are embedded in the base body 12. The upper surfaces of the lead terminals 18A and 18B are exposed at the bottom of the recess 11. The lower surfaces of the lead terminals 18A and 18B are exposed from the bottom surface of the base body 12.

[0018] The light-emitting element 16 is mounted on the lead terminal 18A. The bonding wire 19A electrically connects the electrode of the light-emitting element 16 to the lead terminal 18A. The bonding wire 19B electrically connects the electrode of the light-emitting element 16 to the lead terminal 18B. The protective element 17 is mounted on the lead terminal 18B. The bonding wire 19C electrically connects the electrode of the protective element 17 to the lead terminal 18A.

[0019] A sealing member 22 is positioned within the recess 11. The sealing member 22 comprises a base material 21, a first phosphor 20A, and a second phosphor 20B. The first phosphor 20A and the second phosphor 20B are dispersed within the base material 21.

[0020] When a voltage or current is applied between lead terminals 18A and 18B from the bottom surface of package 10, a voltage or current is applied to the electrodes of the light-emitting element 16 via bonding wires 19A and 19B. As a result, the light-emitting element 16 emits light. The light emitted by the light-emitting element 16 irradiates the first phosphor 20A and the second phosphor 20B, exciting the first phosphor 20A and the second phosphor 20B. The light emitted by the light-emitting element 16 and the light emitted by the first phosphor 20A and the second phosphor 20B pass through the base material 21 and are emitted from the top surface of the sealing member 22.

[0021] The protective element 17 is connected in parallel with the light-emitting element 16 between lead terminals 18A and 18B via a bonding wire 19C. The protective element 17 protects the light-emitting element 16 when static electricity or the like is applied to lead terminals 18A or 18B. The protective element 17 is optional.

[0022] The light-emitting element 16 is a semiconductor light-emitting element such as an LED (Light Emitting Diode) or a semiconductor laser. The main wavelength of the light-emitting element 16 is in the range of 400 nm to 490 nm. The light-emitting element 16 is made of, for example, a nitride-based semiconductor (In Ｘ Al Ｙ Ga １－Ｘ－Ｙ The following is used: N, 0 ≤ X, 0 ≤ Y, X + Y ≤ 1). The protection element 17 is, for example, a Zener diode.

[0023] The substrate 12 is formed of an insulating material that does not easily transmit light emitted by the light-emitting element 16, and is, for example, an organic insulator such as a thermosetting resin or thermoplastic resin, or an inorganic insulator such as Ceramics. As an organic insulator, for example, epoxy resin, silicone resin, phenolic resin, glass epoxy resin, bismaleimidotriazine resin, or polyphthalamide resin can be used. The organic insulator may contain a colorant or filler. As an inorganic insulator, for example, aluminum oxide or aluminum nitride can be used.

[0024] The lead terminals 18A and 18B are made of a material with high electrical and thermal conductivity, such as aluminum, iron, nickel, copper, or alloys thereof. The bonding wires 19A to 19C are made of a material with high electrical conductivity, such as gold or aluminum.

[0025] The base material 21 is formed from a material that transmits light emitted by the light-emitting element 16, and is an organic insulator such as silicone resin (e.g., dimethyl silicone resin, methylphenyl silicone resin, phenyl silicone resin), epoxy resin, etc. The first phosphor 20A and the second phosphor 20B will be described later.

[0026] (Example 2 of the light-emitting device) Figure 4 is a cross-sectional view showing Example 2 of the light-emitting device according to the first embodiment. As shown in Figure 4, the light-emitting device 102 comprises a substrate 30, a sealing member 32, a light-emitting element 36, a protective element 37, a conductive member 34, an adhesive 33, a wavelength converter 24, and a light-transmitting body 25.

[0027] The light-emitting element 36 and the protective element 37 are bonded to the substrate 30 with a conductive member 34 in between. The wavelength converter 24 is bonded to the upper surface of the light-emitting element 36 with an adhesive 33 in between. A light-transmitting body 25 is placed on the wavelength converter 24. The sealing member 32 is placed on the substrate 30 to seal the light-emitting element 36, the protective element 37, the wavelength converter 24, and the light-transmitting body 25. The upper surface of the light-transmitting body 25 is exposed from the upper surface of the sealing member 32.

[0028] Figure 5 is an enlarged view of area V in Figure 4. As shown in Figure 5, an adhesive 33 is sandwiched between the wavelength converter 24 and the light-transmitting body 25 on the light-emitting surface 36A of the light-emitting element 36. The wavelength converter 24 includes a light-transmitting material 23, a first phosphor 20A, and a second phosphor 20B. The first phosphor 20A and the second phosphor 20B are dispersed in the light-transmitting material 23.

[0029] A voltage or current is applied to the electrodes of the light-emitting element 36 via the conductive member 34. As a result, the light-emitting element 36 emits light from its light-emitting surface 36A. The light emitted by the light-emitting element 36 irradiates the first phosphor 20A and the second phosphor 20B via the adhesive 33, exciting the first phosphor 20A and the second phosphor 20B. The light emitted by the light-emitting element 36 and the light emitted by the first phosphor 20A and the second phosphor 20B pass through the light-transmitting material 23 and the light-transmitting body 25 and are emitted from the upper surface of the sealing member 32.

[0030] The configuration of the light-emitting element 36 is the same as that of the light-emitting element 16 described in, for example, the light-emitting device 100. The configuration of the protective element 37 is the same as that of the protective element 17 described in, for example, the light-emitting device 100.

[0031] The substrate material 30 is the same material as the substrate 12 described in the light-emitting device 100, for example. The sealing member 32 is formed of an insulating material that does not easily transmit light emitted by the light-emitting element 16, and is an organic insulator such as epoxy resin, silicone resin, phenolic resin, glass epoxy resin, bismaleimidotriazine resin, or polyphthalamide resin. The organic insulator may contain a colorant or filler.

[0032] The conductive member 34 is, for example, a conductive bump, and is made of gold, a gold alloy, or solder. The adhesive 33 is made of an insulating material that transmits light emitted by the light-emitting element 16, and is an organic insulator such as epoxy resin, silicone resin, phenolic resin, or polyimide resin.

[0033] The light-transmitting body 25 is formed of an insulating material that allows light emitted by the light-emitting element 16 to pass through and has high mechanical strength, and is, for example, an inorganic insulator such as glass or an organic insulator. Glass is, for example, borosilicate glass or quartz glass. Organic insulators are, for example, epoxy resin or silicone resin. The material of the light-transmitting material 23 is, for example, the same as the base material 21 described in the light-emitting device 100. The first phosphor 20A and the second phosphor 20B will be described later.

[0034] (Light-emitting devices) Light-emitting devices 100 and 102 are examples of the first embodiment, and the structure of the light-emitting devices is not limited to light-emitting devices 100 and 102. Light-emitting devices 100 and 102 include light-emitting elements 16 and 36 that emit light having a dominant wavelength in the range of 400 nm to 490 nm, and a first phosphor 20A and a second phosphor 20B that are excited by the light emitted by the light-emitting elements 16 and 36 and emit light. The dominant wavelengths of the light-emitting elements 16 and 36 may be 420 nm to 480 nm, or 430 nm to 460 nm. The first phosphor 20A emits light having a peak wavelength in the range of 500 nm to less than 570 nm, and the second phosphor 20B emits light having a peak wavelength in the range of 570 nm to 615 nm. There may be one type of phosphor or three or more types.

[0035] (Emission Spectrum) (First integrated value 51A of emission intensity in the wavelength range 51 of 600 nm to 780 nm) The first integrated value 51A is less than 22.5% of the second integrated value 50A of emission intensity in the wavelength range 50 of 380 nm to 780 nm. The first integrated value 51A may be less than 21.5%, less than 21.0%, or less than 20.0% of the second integrated value 50A. This allows for a larger amount of the wavelength component of luminous sensitivity in the emission spectrum of the light-emitting device. Therefore, the luminous flux can be increased. If the first integrated value 51A is too small, it is difficult to achieve the desired chromaticity. From this viewpoint, it is preferable that the first integrated value 51A is 10.0% or more of the second integrated value 50A.

[0036] (Third integrated value 52A of emission intensity in the wavelength range 52 of 640 nm to 780 nm) The third integrated value 52A is less than 7.0% of the second integrated value 50A. The third integrated value 52A may be less than 6.5%, less than 6.0%, or less than 5.5% of the second integrated value 50A. This allows for a larger amount of the wavelength component of luminous sensitivity in the emission spectrum of the light-emitting device. Therefore, the luminous flux can be increased. If the third integrated value 52A is too small, it is difficult to achieve the desired chromaticity. From this viewpoint, it is preferable that the third integrated value 52A is 1.0% or more of the second integrated value 50A.

[0037] (Fourth integrated value 53A of emission intensity in the wavelength range 53 of 470 nm to 520 nm) The fourth integrated value 53A is less than 14.4% of the second integrated value 50A. The fourth integrated value 53A may also be less than 14.0%, less than 13.0%, or less than 12.5% ​​of the second integrated value 50A. This allows for a larger amount of the wavelength component of luminous sensitivity in the emission spectrum of the light-emitting device. Therefore, the luminous flux can be increased. If the fourth integrated value 53A is too small, it is difficult to achieve the desired chromaticity. From this viewpoint, it is preferable that the fourth integrated value 53A is 5.0% or more of the second integrated value 50A.

[0038] (Sum of the fourth integral value 53A and the third integral value 52A) The sum of the fourth integral value 53A and the third integral value 52A is less than 23.0% of the second integral value 50A. The sum of the fourth integral value 53A and the third integral value 52A may also be less than 21.0%, less than 20.0%, or less than 19.5% of the second integral value 50A. This allows for a larger amount of the wavelength component of luminous sensitivity in the emission spectrum of the light-emitting device. Therefore, the luminous flux can be increased. If the sum of the fourth integral value 53A and the third integral value 52A is too small, it is difficult to achieve the desired chromaticity. From this viewpoint, it is preferable that the sum of the fourth integral value 53A and the third integral value 52A is 10.0% or more of the second integral value 50A.

[0039] (Peak wavelength of phosphors) The first phosphor 20A emits light having a peak wavelength in the range of 500 nm to less than 570 nm. The peak wavelength of the first phosphor 20A may also be 510 nm to 550 nm, or 520 nm to 540 nm. This allows for a higher luminous flux. The second phosphor 20B emits light having a peak wavelength in the range of 570 nm to 615 nm. The peak wavelength of the second phosphor 20B may also be 580 nm to 600 nm. This allows for a higher luminous flux.

[0040] (Chromaticity Coordinates of the First Phosphor 20A) The chromaticity of the first light emitted by the first phosphor 20A is within the following region in the xy chromaticity coordinates of the CIE1931 chromaticity diagram by the International Commission on Illumination (CIE). The chromaticity coordinates (x, y) have (x = 0.23, y = 0.70) as the first point, (x = 0.48, y = 0.70) as the second point, (x = 0.48, y = 0.45) as the third point, and (x = 0.23, y = 0.45) as the fourth point. The region is defined by a first straight line connecting the first point and the second point, a second straight line connecting the second point and the third point, a third straight line connecting the third point and the fourth point, and a fourth straight line connecting the fourth point and the first point.

[0041] (Chromaticity Coordinates of the Second Phosphor 20B) The chromaticity of the second light emitted by the second phosphor 20B is within the following region in the xy chromaticity coordinates of the CIE1931 chromaticity diagram. The region has chromaticity coordinates (x, y) with (x = 0.48, y = 0.35) as the fifth point, (x = 0.63, y = 0.35) as the sixth point, (x = 0.63, y = 0.53) as the seventh point, and (x = 0.48, y = 0.53) as the eighth point. The region is defined by a fifth straight line connecting the fifth point and the sixth point, a sixth straight line connecting the sixth point and the seventh point, a seventh straight line connecting the seventh point and the eighth point, and an eighth straight line connecting the eighth point and the fifth point.

[0042] (The First Phosphor 20A) The first phosphor 20A includes at least one selected from the group consisting of a rare earth aluminate phosphor having a composition represented by the following formula (1A), a rare earth aluminate phosphor having a composition represented by the following formula (1B), a first nitride phosphor having a composition represented by the following formula (1C), and a first oxynitride phosphor having a composition represented by the following formula (1D).

[0043] (Y ａ Lu １－ａ ) ｂ (Al ｃ Ga １－ｃ ) ｄ O １２ :Ce ｕ (In formula (1A), a, b, c, d, and u are numbers that satisfy 0 ≤ a ≤ 1, 2.8 ≤ b ≤ 3.2, 0 ≤ c ≤ 1, 4.8 ≤ d ≤ 5.2, and 0.009 ≤ u ≤ 0.6, respectively.)

[0044] (Y ｅ Gd１－ｅ ) ｆ Al ｇ O １２ : Ce ｖ (1B) (In equation (1B), e, f, g, and v are numbers that satisfy 0 ≤ e ≤ 1, 2.8 ≤ f ≤ 3.2, 4.8 ≤ g ≤ 5.2, and 0.009 ≤ v ≤ 0.6, respectively.)

[0045] La ｈ Y ｉ Gd ｊ Si ６ N ８＋ｋ : Ce ｗ (1C) (In equation (1C), h, i, j, k, and w are numbers that satisfy 1.5 ≤ h ≤ 3.0, 0 ≤ i ≤ 1.0, 0 ≤ j ≤ 2.0, 2.0 ≤ k ≤ 4.0, and 0 < w ≤ 1.0, respectively.)

[0046] Si ６－ｍ Al ｍ O ｍ N ８－ｍ :Eu ｘ (1D) (In equation (1D), m and x are numbers that satisfy 0 < m ≤ 0.2 and 0 < x ≤ 4.2, respectively.)

[0047] (Second phosphor 20B) The second phosphor 20B includes at least one selected from the group consisting of a second nitride phosphor having a composition represented by the following formula (2A) and a second oxynitride phosphor having a composition represented by the following formula (2B).

[0048] (Ba ｌ Sr ｎ ) ２ Si ５ N ８－ｏ :Eu ｙ (2A) (In equation (2A), l, n, o, and y are numbers that satisfy 0.500 ≤ l ≤ 0.995, 0 ≤ n ≤ 0.50, 0 ≤ o ≤ 0.50, 0.9 < l + n + y ≤ 1.0, and 0.001 ≤ y ≤ 0.03, respectively.)

[0049] M ｐ Si １２－（ｑ＋ｒ） Al ｑ＋ｒ O ｒ N １６－ｒ :Eu ｚ(2B) (In formula (2B), M is at least one element selected from the group consisting of Li, Mg, Ca, Sr, Y, and lanthanide elements (excluding La and Ce), and p, q, r, and z are numbers satisfying 0 < p ≤ 2.0, 2.0 ≤ q ≤ 6.0, 0 ≤ r ≤ 1.0, and 0 < z ≤ 1.0, respectively.)

[0050] In equation (2A), 0.550 ≤ l ≤ 0.995 is more preferable, and 0.600 ≤ l ≤ 0.995 is even more preferable. 0 ≤ n ≤ 0.45 is more preferable, and 0 ≤ n ≤ 0.40 is even more preferable. 0 ≤ o ≤ 0.45 is more preferable, and 0 ≤ o ≤ 0.40 is even more preferable. 0.9 < l + n + y ≤ 0.999 is more preferable, and 0.9 < l + n + y ≤ 0.998 is even more preferable. 0.001 ≤ y ≤ 0.025 is more preferable, and 0.001 ≤ y ≤ 0.02 is even more preferable.

[0051] In equation (2B), 0 < p ≤ 1.95 is more preferable, and 0 < p ≤ 1.9 is even more preferable. 2.0 ≤ q ≤ 5.0 is more preferable, and 2.0 ≤ q ≤ 4.0 is even more preferable. 0 ≤ r ≤ 0.8 is more preferable, and 0 ≤ r ≤ 0.5 is even more preferable. 0 < z ≤ 0.5 is more preferable, and 0 < z ≤ 0.3 is even more preferable.

[0052] (Chromatic coordinates, color temperature, and color deviation duv of the light emitted by the light-emitting device) When the light-emitting device is used in lighting fixtures such as vehicle headlights, it is preferable that the chromatic coordinates of the light emitted by the light-emitting device be within the range of white according to the ECE (Economic Commission for Europe) standard. According to the ECE standard, the chromaticity of the light emitted by the light-emitting device is as follows: In the xy chromaticity coordinates of the CIE 1931 chromaticity diagram, the chromaticity coordinates (x, y) are defined as follows: (x = 0.3100, y = 0.2825) as the first point, (x = 0.3100, y = 0.3484) as the second point, (x = 0.4530, y = 0.4400) as the third point, (x = 0.5000, y = 0.4400) as the fourth point, (x = 0.5000, y = 0.3820) as the fifth point, and (x = 0.4427, y = 0.3820) as the sixth point. At this time, the chromaticity of the light emitted by the light-emitting device is within the region defined by the first straight line connecting the first and second points, the second straight line connecting the second and third points, the third straight line connecting the third and fourth points, the fourth straight line connecting the fourth and fifth points, the fifth straight line connecting the fifth and sixth points, and the sixth straight line connecting the sixth point and the first point.

[0053] From the viewpoint of making the light emitted by the light-emitting device white light, the color temperature of the light emitted by the light-emitting device is preferably 5000K to 7000K, and more preferably 5000K to 6500K. The color temperature of the light emitted by the light-emitting device may also be, for example, 5600K to 6300K or 5800K to 6100K.

[0054] From the viewpoint of improving the visibility of the object, the color deviation duv of the light emitted by the light-emitting device is preferably -0.02 or more and 0.02 or less, more preferably -0.02 or more and 0.01 or less, and even more preferably -0.02 or more and 0.00 or less.

[0055] (Second Embodiment) The second embodiment is an example of a lamp using the light-emitting device according to the first embodiment. As an example of a lamp, a vehicle headlight will be used. Figure 6 is a cross-sectional view of the lamp according to the second embodiment. The lamp 104 shown in Figure 6 is installed, for example, on the right side of the front of the vehicle. The lamp 104 comprises a lamp body 41, an outer lens 42, a plurality of substrates 43, a plurality of light-emitting devices 102, an optical filter 44, and a light guide member 45. The outer lens 42 is fitted into the lamp body 41 and together with the lamp body 41 forms a lamp chamber. The plurality of substrates 43 are arranged on the lamp body 41 at the rear of the lamp chamber. The plurality of light-emitting devices 102 are arranged in front of the plurality of substrates 43. The optical filter 44 is fixed to the lamp body 41 by a fixing device and is arranged in front of the light-emitting devices 102. The light guide member 45 is arranged in front of the optical filter 44 to the right.

[0056] When the lighting control unit 40 supplies voltage or current to the light-emitting device 102 via the substrate 43, the light-emitting device 102 emits light. The light passes through the optical filter 44 and becomes light having the desired wavelength. The light that has passed through the optical filter 44 is emitted forward through the outer lens 42. The light guide member 45 directs a portion of the light to the right.

[0057] The luminaire only needs to be equipped with the light-emitting device of the first embodiment, and does not have to be a vehicle headlight. The luminaire may be, for example, an indoor light fixture or an outdoor street light. By using the light-emitting device of the first embodiment in the luminaire, the luminous flux can be increased.

[0058] The following describes an example of the first embodiment.

[0059] A light-emitting device 100 according to Example 1 of the first embodiment was fabricated. A nitride semiconductor light-emitting diode with a dominant wavelength of 450 nm was used as the light-emitting element 16. The emission spectrum of the light-emitting device 100 was measured using an optical measurement system combining a spectrophotometer (product name: PMA-11, manufactured by Hamamatsu Photonics K.K.) and an integrating sphere. The peak wavelength, full width at half maximum, and chromaticity coordinates of the first phosphor 20A and the second phosphor 20B were measured at room temperature (25°C ± 5°C) by irradiating the first phosphor 20A and the second phosphor 20B with excitation light with a peak wavelength of 450 nm and using a quantum efficiency measuring device (product name: QE-2000, manufactured by Otsuka Electronics Co., Ltd.). The particle sizes of the first phosphor 20A and the second phosphor 20B are within the range of 10 μm to 35 μm, where the central particle size Dm at which the cumulative frequency in the volume-based particle size distribution measured by laser diffraction scattering method reaches 50% is 10 μm or more. Laser diffraction scattering is a method for measuring particle size without distinguishing between primary and secondary particles by utilizing the scattered light from a laser beam irradiated onto the particles.

[0060] Table 1 shows the first phosphor 20A, the second phosphor 20B, their concentrations, the concentration of the first phosphor, and the concentration of the second phosphor in the fabricated light-emitting device. The concentration indicates the total concentration of the first phosphor 20A and the second phosphor 20B relative to the base material 21. The concentration of the first phosphor is the concentration of the first phosphor 20A relative to the total of the first phosphor 20A and the second phosphor 20B, and is expressed in mass percent. The concentration of the second phosphor is the concentration of the second phosphor 20B relative to the total of the first phosphor 20A and the second phosphor 20B, and is expressed in mass percent.

[0061]

[0062] As shown in Table 1, Comparative Example 1 includes phosphor 1 as the first phosphor 20A, but does not include the second phosphor 20B. Comparative Example 2 includes phosphor 2 as the first phosphor 20A, and includes phosphors 9 and 10 as the second phosphor 20B. Examples 1 to 3 and Reference Example 1 include phosphor 2 as the first phosphor 20A, and include any of phosphors 11 to 14 as the second phosphor 20B. Examples 4, 5, Reference Example 2 and Reference Example 3 include phosphor 3 as the first phosphor 20A, and include any of phosphors 11, 12, 14 to 16 as the second phosphor 20B. Examples 7 to 9 include any of phosphors 4 to 6 as the first phosphor 20A, and include phosphor 12 as the second phosphor 20B. Comparative Example 3 includes phosphors 1 and 7 as the first phosphor 20A, but does not include the second phosphor 20B. Examples 10, 11, and 12 contain the same first phosphor 20A and second phosphor 20B as in Examples 2, 7, and 9, respectively. In Examples 10, 11, and 12, the concentration of the first phosphor 20A is lower and the concentration of the second phosphor 20B is higher compared to Examples 2, 7, and 9, respectively.

[0063] Table 2 shows the composition, empirical formula, peak wavelength, full width at half maximum, and chromaticity coordinates of the first phosphor 20A.

[0064]

[0065] As shown in Table 2, phosphor 1 has the composition formula Y ３ Al ５ O １２ This is YAG doped with Ce. Phosphor 2 is Y ３ (Al, Ga) ５ O １２ This is G-YAG doped with Ce. G-YAG has a composition represented by formula (1A) a=1, b=3, 0<c<1 and d=5. Phosphors 3 to 5 are Lu ３ (Al, Ga) ５ O １２ This is G-LAG doped with Ce. G-LAG has a composition represented by formula (1A) a=0, b=3, 0<c<1 and d=5. The phosphor 6 is La ３ Si ６ N １１This is an LSN doped with Ce. The LSN has a composition represented by formula (1C) where h=3, i=0, j=0, and k=3. The phosphor 7 is (Y, Gd) ３ Al ５ O １２ This is GdYAG doped with Ce. GdYAG has a composition represented by formula (1B) with f=3 and g=5. The phosphor 8 is Lu ３ Al ５ O １２ This is LAG doped with Ce. The LAG has a composition represented by formula (1A) a=0, b=3, c=1, and d=5.

[0066] Table 3 shows the composition, empirical formula, peak wavelength, full width at half maximum, and chromaticity coordinates of the second phosphor 20B.

[0067]

[0068] As shown in Table 3, phosphors 9, 10, and 15 have the compositional formula (Sr, Ca)AlSiN ３ This is SCASN doped with Eu. Phosphors 11, 12, and 16 have the composition formula (Ba, Sr). ２ Si ５ N ８ This is BSESN doped with Eu. BSESN has a composition represented by formula (2A) where 0 < n and o = 0. Phosphors 13 and 14 have composition formulas Ca ｘ (Si, Al) １２ (O, N) １６ It is an α-sialon doped with Eu. It has a composition in formula (2B) where M is Ca.

[0069] Table 4 shows the luminous flux ratios for each sample, the first integral value 51A / second integral value 50A, the third integral value 52A / second integral value 50A, the fourth integral value 53A / second integral value 50A, and (third integral value 52A + fourth integral value 53A) / second integral value 50A. The luminous flux ratio is the ratio of the luminous flux of each sample to the luminous flux of Comparative Example 1.

[0070]

[0071] Table 5 shows the chromaticity coordinates, color temperature, and color deviation (duv) of the light emitted by each sample.

[0072]

[0073] The emission spectra of Comparative Examples 1 to 3, Examples 1 to 13, and Reference Examples 1 to 3 will be described below. In the explanation of Figures 7 to 12, for simplification, "first integral value 51A / second integral value 50A", "third integral value 52A / second integral value 50A", "fourth integral value 53A / second integral value 50A", and "(third integral value 52A + fourth integral value 53A) / second integral value 50A" will also simply be referred to as "first integral value 51A", "third integral value 52A", "fourth integral value 53A", and "sum of third integral value 52A and fourth integral value 53A", respectively.

[0074] Figure 7 shows the emission spectra and relative luminous efficiency curves for Example 1, Example 2, Comparative Example 1, and Comparative Example 2. Comparative Example 1 does not contain the second phosphor 20B, as shown in Tables 1 and 2, and the peak wavelength of the first phosphor 20A is 560 nm. Comparative Example 2 includes phosphor 2 with a peak wavelength of 532 nm as the first phosphor 20A, and includes phosphors 9 and 10 with peak wavelengths of 620 nm or higher as the second phosphor 20B.

[0075] In Comparative Example 1, the peak wavelength of the first phosphor 20A is located near the peak wavelength of the relative luminous efficiency. However, the first integral value 51A, with a wavelength of 600 nm or more, is 22.8%, and the third integral value 52A, with a wavelength of 640 nm or more, is 9.5%, both of which are large. As a result, the luminous flux is low. In Comparative Example 2, the first phosphor 20A and the second phosphor 20B are included. Since the peak wavelengths of phosphors 9 and 10 of the second phosphor 20B are 620 nm or more, the first integral value 51A is 23.4%, which is larger than in Comparative Example 1, and the third integral value 52A is 9.2%, which is about the same as in Comparative Example 1. Also, because the peak wavelength of phosphor 2 of the first phosphor 20A is short, the fourth integral value 53A is 14.4%, which is larger than the 7.4% in Comparative Example 1. The sum of the third integral value 52A and the fourth integral value 53A is 23.6%, which is larger than the 16.9% in Comparative Example 1. As a result, the luminous flux ratio is 96.9%, which is lower than that of Comparative Example 1.

[0076] In Example 1, the same phosphor 2 as in Comparative Example 2 is used as the first phosphor 20A, but as the second phosphor 20B, phosphor 11 is used, which has a peak wavelength of 592 nm, shorter than the peak wavelengths of phosphors 9 and 10 in Comparative Example 2. As a result, the first integral value 51A is 19.4% and the third integral value 52A is 6.4%, which are smaller than those of Comparative Examples 1 and 2. By shortening the peak wavelength of the second phosphor 20B, the first phosphor concentration can be reduced to 71.6%, which is smaller than that of Comparative Example 2. Therefore, the fourth integral value 53A can be reduced to 12.4%, which is smaller than that of Comparative Example 2. The sum of the third integral value 52A and the fourth integral value 53A can be reduced to 18.8%, which is smaller than that of Comparative Example 2. As a result, the luminous flux ratio is 101.9%, which is higher than that of Comparative Examples 1 and 2.

[0077] In Example 2, the same phosphor 2 as in Comparative Example 2 is used as the first phosphor 20A, but as the second phosphor 20B, phosphor 12 is used, which has a peak wavelength of 581 nm, shorter than the peak wavelengths of phosphors 9 and 10 in Comparative Example 2. As a result, the first integral value 51A is reduced to 17.4%, and the third integral value 52A is reduced to 5.4%. By shortening the peak wavelength of the second phosphor 20B, the first phosphor concentration can be reduced to 67.5%, which is lower than in Comparative Example 2, and the fourth integral value 53A can be reduced to 11.2%. The sum of the third integral value 52A and the fourth integral value 53A can be reduced to 16.6%. As a result, the luminous flux ratio is 105.3%, which is higher than in Comparative Example 1, Comparative Example 2, and Example 1.

[0078] Figure 8 shows the emission spectra and relative luminous efficiency curves for Example 3, Comparative Example 1, Comparative Example 2, and Reference Example 1. The first phosphor 20A in Comparative Example 2, Example 3, and Reference Example 1 is the same as phosphor 2. The second phosphor 20B in Reference Example 1 is phosphor 13 with a peak wavelength of 602 nm. The peak wavelength of phosphor 13 in the second phosphor 20B of Reference Example 1 is shorter than the peak wavelengths of phosphors 9 and 10 in Comparative Example 2, but the full width at half maximum is wider, so the first integral value 51A and the third integral value 52A are 20.7% and 7.1%, respectively, which are larger than in Example 1 and Example 2. The first phosphor concentration is 90%, which is higher than in Example 1 and Example 2, and the fourth integral value 53A is 12.5%, which is higher than in Example 1 and Example 2. The sum of the third integral value 52A and the fourth integral value 53A is 19.6%, which is larger than in Example 1 and Example 2. As a result, the luminous flux ratio is 99.4%, which is lower than that of Comparative Example 1.

[0079] The second phosphor 20B in Example 3 is phosphor 14 with a peak wavelength of 597 nm, which is shorter than the peak wavelength of phosphor 13 used in Reference Example 1. The second phosphor concentration in Example 3 is 15.85%, which is lower than that of Examples 1 and 2 but higher than that of Reference Example 1. The first integral value 51A and the third integral value 52A are 20.2% and 6.8%, respectively, which are lower than those in Reference Example 1. The first phosphor concentration is 84.15%, which is lower than that of Reference Example 1, and the fourth integral value 53A is 12.5%, which is about the same as that of Reference Example 1. The sum of the third integral value 52A and the fourth integral value 53A is 19.2%, which is lower than that of Reference Example 1. As a result, the luminous flux ratio is 101.0%, which is higher than that of Comparative Example 1 and Reference Example 1.

[0080] As shown in Comparative Example 2, Examples 1 to 3, and Reference Example 1, even if the first phosphor 20A is the same, the first integral value 51A, the third integral value 52A, and the fourth integral value 53A can be reduced by shortening the peak wavelength of the second phosphor 20B. The sum of the third integral value 52A and the fourth integral value 53A can be reduced. This allows the luminous flux to be increased.

[0081] Figure 9 shows the emission spectra and relative luminous efficiency curves for Example 4, Example 5, Comparative Example 1, and Reference Example 3. The first phosphor 20A in Reference Example 3, Example 4, and Example 5 is the same as phosphor 3. The second phosphor 20B in Reference Example 3, Example 4, and Example 5 are phosphor 16, phosphor 11, and phosphor 12, respectively, and are BSESN. The peak wavelengths of phosphor 16, phosphor 11, and phosphor 12 are 598 nm, 592 nm, and 581 nm, respectively. The second phosphor concentration is 6.0% in Reference Example 3 and 16.5% in Examples 4 and 5. The first integral value 51A is 19.8% in Reference Example 3, 18.5% in Example 4, and 15.9% in Example 5. The third integral value 52A is 7.0% in Reference Example 3, 5.8% in Example 4, and 4.4% in Example 5. The fourth integral value 53A is 14.4% in Reference Example 3, 14.2% in Example 4, and 12.2% in Example 5. The sum of the third integral value 52A and the fourth integral value 53A is 21.4% in Reference Example 3, 20.0% in Example 4, and 16.6% in Example 5. As a result, the luminous flux ratio is 99.5% in Reference Example 3, 102.1% in Example 4, and 104.5% in Example 5.

[0082] As shown in Reference Example 3, Example 4, and Example 5, even if the first phosphor 20A and the composition of the second phosphor 20B are the same, changing the composition ratio of the second phosphor 20B changes the peak wavelength and thus the luminous flux. Shortening the peak wavelength of the second phosphor 20B reduces the first integral value 51A, the third integral value 52A, and the fourth integral value 53A, resulting in a higher luminous flux.

[0083] Figure 10 shows the emission spectra and relative luminous efficiency curves for Example 6, Comparative Example 1, and Reference Example 2. The first phosphor 20A in Reference Example 2 and Example 6 is the same as phosphor 3. The second phosphor 20B in Reference Example 2 is SCASN of phosphor 15, with a peak wavelength of 618 nm. The second phosphor 20B in Example 6 is α-sialon of phosphor 14, with a peak wavelength of 597 nm. The second phosphor concentration is 4.3% in Reference Example 2 and 10.3% in Example 6. The first integral value 51A is 22.0% in Reference Example 2 and 20.0% in Example 6. The third integral value 52A is 7.6% in Reference Example 2 and 6.5% in Example 6. The fourth integral value 53A is 17.2% in Reference Example 2 and 14.1% in Example 6. The sum of the third integral value 52A and the fourth integral value 53A is 24.9% in Reference Example 2 and 20.6% in Example 6. As a result, the luminous flux ratio is 96.7% in Reference Example 2 and 100.3% in Example 6.

[0084] As shown in Reference Example 2, Reference Example 3, and Examples 4 to 6, even when the composition of the second phosphor 20B is changed while keeping the first phosphor 20A the same, changing the peak wavelength of the second phosphor 20B changes the luminous flux. When the peak wavelength of the second phosphor 20B is shortened, the first integral value 51A, the third integral value 52A, and the fourth integral value 53A decrease, and the luminous flux increases.

[0085] Figure 11 shows the emission spectra and relative luminous efficiency curves for Examples 2, 5, and 7-9. The first phosphor 20A in Examples 2, 5, and 7-9 are different, being phosphors 2 to 6, respectively. The second phosphor 20B in Examples 2, 5, and 7-9 is the same, being phosphor 12. The peak wavelengths of phosphors 2 to 6 are 532 nm, 521 nm, 518 nm, 519 nm, and 535 nm, respectively. The peak wavelengths of phosphors 2 and 6 are almost the same, and the peak wavelengths of phosphors 3, 4, and 5 are almost the same. Thus, in Examples 2 and 9, the peak wavelengths of the first phosphor 20A are long, at 532 nm and 535 nm. In Examples 5, 7, and 8, the peak wavelengths of the first phosphor 20A are short, at 521 nm to 518 nm.

[0086] In Examples 2 and 9, where the peak wavelength of the first phosphor 20A is long, the first integral value 51A is 17.4% and 19.5%, respectively, which is greater than the first integral value 51A of Examples 5, 7, and 8, where the peak wavelength of the first phosphor 20A is short, which is 15.9%, 16.2%, and 16.1%. In Examples 2 and 9, the third integral value 52A is 5.4% and 6.4%, respectively, which is greater than the third integral value 52A of Examples 5, 7, and 8, which is 4.4%, 4.6%, and 4.5%. In Examples 2 and 9, the fourth integral value 53A is 11.2% and 8.3%, which is smaller than the fourth integral value 53A of Examples 5, 7, and 8, which is 12.2%, 12.8%, and 13.2%. In Examples 2 and 9, the sum of the third integral value 52A and the fourth integral value 53A is 16.6% and 14.7%, respectively, which is smaller than the sum of the third integral value 52A and the fourth integral value 53A in Examples 5, 7, and 8, which is 16.6%, 17.3%, and 17.7%. The luminous flux ratios in Examples 2 and 9 are 105.3% and 105.3%, respectively, which is higher than the luminous flux ratios in Examples 5, 7, and 8, which are 104.5%, 103.3%, and 102.7%.

[0087] As shown in Examples 2, 5, and 7-9, when the peak wavelength of the first phosphor 20A is increased while keeping the second phosphor 20B the same, the first integral value 51A and the third integral value 52A increase, but the fourth integral value 53A decreases. As a result, the luminous flux increases.

[0088] Figure 12 shows the emission spectra and relative luminous efficiency curves for Comparative Example 3 and Examples 10 to 13. As shown in Table 5, the color deviation DUV is 0.00 for Comparative Example 1, Comparative Example 2, Reference Examples 1 to 3, and Examples 1 to 9. In contrast, the color deviation DUV is -0.01 for Comparative Example 3 and Examples 10 to 12. By setting the color deviation DUV to approximately -0.01, the visibility of objects is improved when the light-emitting device is used as a vehicle headlight.

[0089] In Comparative Example 3, as shown in Tables 1 and 2, the second phosphor 20B is not included, but phosphor 1 with a peak wavelength of 560 nm and phosphor 7 with a peak wavelength of 568 nm are included. In Comparative Example 3, the color deviation duv can be made to approximately -0.01. However, the first integral value 51A and the third integral value 52A are large, at 24.0% and 10.5%, respectively, and the luminous flux ratio is 94.4%, which is smaller than the luminous flux ratio of Comparative Example 1.

[0090] In Examples 10 to 12, the concentration of the first phosphor 20A is lower and the concentration of the second phosphor 20B is higher than in Examples 2, 7, and 9, respectively. As a result, the first integral value 51A and the third integral value 52A in Examples 10 to 12 are about the same as or greater than the first integral value 51A and the third integral value 52A in Examples 2, 7, and 9, respectively. The fourth integral value 53A in Examples 10 to 12 is smaller than the fourth integral value 53A in Examples 2, 7, and 9, respectively. The sum of the third integral value 52A and the fourth integral value 53A in Examples 10 to 12 is smaller than the sum of the third integral value 52A and the fourth integral value 53A in Examples 2, 7, and 9, respectively. The luminous flux ratios in Examples 10 to 12 are smaller than the luminous flux ratios in Examples 2, 7, and 9, respectively, but the color deviation duv can be set to -0.01 and the luminous flux ratio can be made larger than that of Comparative Examples 1 to 3.

[0091] As in Example 13, even when phosphor 8 is used as the first phosphor 20A, the first integral value 51A and the third integral value 52A can be made smaller than the first integral value 51A and the third integral value 52A of Comparative Examples 1 to 3. As a result, the luminous flux of Example 13 can be made larger than that of Comparative Example 1.

[0092] As shown in Figures 7 to 12 and Tables 1 to 5, the luminous flux can be increased by reducing the first integral value 51A, the third integral value 52A, and the fourth integral value 53A. In Table 4, values ​​where the luminous flux ratio is greater than 100% are shown in bold, values ​​where the first integral value 51A is less than 22.5% are shown in bold, and values ​​where the third integral value 52A is less than 7.0% are shown in bold. From Table 4, by setting the first integral value 51A to less than 22.5% and the third integral value 52A to less than 7.0%, the luminous flux ratio can be increased to more than 100%. By setting the third integral value 52A to less than 6.5%, the luminous flux ratio can be set to 101.9% or higher. By setting the third integral value 52A to less than 6.0%, the luminous flux ratio can be set to 102.1% or higher.

[0093] In Table 4, values ​​where the fourth integral value 53A is less than 14.4% are shown in bold. By setting the first integral value 51A to less than 22.5%, the third integral value 52A to less than 7.0%, and the fourth integral value 53A to less than 14.4%, the luminous flux ratio can be made higher than 100%. By setting the first integral value 51A to less than 22.5%, the third integral value 52A to less than 7.0%, and the fourth integral value 53A to less than 12.5%, the luminous flux ratio can be made 101.9% or higher.

[0094] As shown in Figure 11, when there is a trade-off between the third integral value 52A and the fourth integral value 53A, it is preferable to reduce the sum of the third integral value 52A and the fourth integral value 53A. In Table 4, values ​​where the sum of the third integral value 52A and the fourth integral value 53A is less than 23.0% are shown in bold. By setting the first integral value 51A to less than 22.5% and the third integral value 52A to less than 7.0%, and the sum of the third integral value 52A and the fourth integral value 53A to less than 23.0%, the luminous flux ratio can be made higher than 100%. By setting the first integral value 51A to less than 22.5% and the third integral value 52A to less than 7.0%, and the sum of the third integral value 52A and the fourth integral value 53A to less than 19.5%, the luminous flux ratio can be made 101.0% or higher.

[0095] To reduce the first integral value 51A, the third integral value 52A, and the fourth integral value 53A, it is preferable to appropriately set the peak wavelength of the first phosphor 20A and the peak wavelength of the second phosphor 20B. As for the first phosphor 20A, the luminous flux of Example 5, which has phosphor 3, is high, and the luminous fluxes of Examples 2 and 9, which have phosphors 2 and 6 respectively, are high. Therefore, the peak wavelength of the first phosphor 20A is preferably 520 nm or higher, and more preferably 530 nm or higher. As for the second phosphor 20B, the luminous flux of Examples 2, 5, and 8, which have phosphor 12, is high. Therefore, the peak wavelength of the second phosphor 20B is preferably 600 nm or lower, and more preferably 585 nm or lower. Also, the full width at half maximum of the emission spectrum of phosphor 12 is 68 nm. In this way, the second phosphor 20B can achieve a high luminous flux by having a narrow full width at half maximum. The full width at half maximum (FWHM) of the second phosphor 20B is preferably 95 nm or less, more preferably 90 nm or less, even more preferably 85 nm or less, and even more preferably 80 nm or less. From the viewpoint of achieving the desired chromaticity, the FWHM of the second phosphor 20B is preferably 50 nm or more. In particular, for the second phosphor 20B, it is preferable that the peak wavelength is 600 nm or less and the FWHM of the emission spectrum is 85 nm or less, and it is more preferable that the peak wavelength is 585 nm or less and the FWHM of the emission spectrum is 80 nm or less.

[0096] Examples 1 to 9, in which the luminous flux ratio is higher than 100%, include phosphor 11, phosphor 12, or phosphor 14 as the second phosphor 20B. Therefore, it is preferable that the second phosphor 20B includes BSESN or α-sialon.

[0097] Figure 13 shows the x and y chromaticity coordinates of the light emitted by a phosphor. In Figure 13, the line defining the horseshoe-shaped outline is the monochromatic light trajectory 60. The black circle 61 indicates the x and y chromaticity coordinates of phosphors 1 to 6, with phosphor 20A being the first phosphor. Region 61A is defined by the straight line connecting the first point 63A and the second point 63B, the straight line connecting the second point 63B and the third point 63C, the straight line connecting the third point 63C and the fourth point 63D, and the straight line connecting the fourth point 63D and the first point 63A. The first point 63A is (x = 0.23, y = 0.70), the second point 63B is (x = 0.48, y = 0.70), the third point 63C is (x = 0.48, y = 0.45), and the fourth point 63D is (x = 0.23, y = 0.45). At this time, the chromaticity coordinates of phosphors 1 to 6 are located within region 61A.

[0098] Even if we define the first point 63A as (x=0.25, y=0.65), the second point 63B as (x=0.46, y=0.65), the third point 63C as (x=0.46, y=0.50), and the fourth point 63D as (x=0.25, y=0.50), the chromaticity coordinates of phosphors 1 to 6 are located within region 61A.

[0099] The white circle 62 represents the second phosphor 20B and indicates the xy chromaticity coordinates of phosphors 9 to 16. Region 62A is defined by the lines connecting the fifth point 64A and the sixth point 64B, the sixth point 64B and the seventh point 64C, the seventh point 64C and the eighth point 64D, and the eighth point 64D and the fifth point 64A. The fifth point 64A is (x=0.48, y=0.35), the sixth point 64B is (x=0.63, y=0.35), the seventh point 64C is (x=0.63, y=0.53), and the eighth point 64D is (x=0.48, y=0.53). In this case, the chromaticity coordinates of phosphors 11 to 14 and phosphor 16 are located within region 62A.

[0100] Even if the fifth point 64A is (x=0.48, y=0.40), the sixth point 64B is (x=0.60, y=0.40), the seventh point 64C is (x=0.60, y=0.53), and the eighth point 64D is (x=0.48, y=0.53), the chromaticity coordinates of phosphors 11 to 14 and phosphor 16 are located within region 62A.

[0101] (Temperature Characteristics of the Second Phosphor) The temperature characteristics of silicate phosphor, SCASN (phosphor 15), BSESN (phosphor 12), and α-sialon (phosphor 14) were measured as the second phosphor 20B. The measurement was performed by irradiating the second phosphor 20B with 450 nm excitation light obtained by spectrally analyzing light from a Xe lamp while the temperature of the second phosphor 20B was varied, and measuring the energy in the wavelength range of 470 nm to 730 nm. A spectrofluorometer (product name: F-4500, manufactured by Hitachi High-Tech Science Corporation) was used as the measuring instrument. The silicate phosphor emits light with a peak wavelength in the range of 570 nm to 615 nm. The compositional formula of the silicate phosphor is (Ba ｘ Sr ｙ Eu ｚ ) ３ SiO ５ (0 ≤ x < 1, 0 ≤ y < 1, and 0 < z < 1).

[0102] For silicate phosphors, the energy retention rate at 300°C is approximately 35%. In contrast, the energy retention rates at 300°C are approximately 83% for SCASN, 61% for BSESN, and 88% for α-Sialon. Thus, SCASN, BSESN, and α-Sialon exhibit better temperature characteristics compared to silicate phosphors.

[0103] In Examples 1 to 13, the chromaticity coordinate of the light emitted by the light-emitting device can be within the range of white in the ECE standard. The color temperature of the light emitted by the light-emitting device is 5898K to 5999K, and can be in the range of 5000K to 7000K. As in Examples 1 to 9 and Example 13, even if the color deviation duv of the light emitted by the light-emitting device is about 0.00, the luminous flux ratio can be greater than 100%, and even if the color deviation duv of the light emitted by the light-emitting device is about -0.01, improving the visibility of the object, the luminous flux ratio can be greater than 100%.

[0104] Although preferred embodiments have been described in detail above, the invention is not limited to the embodiments described above, and various modifications and substitutions can be made to the embodiments described above without departing from the scope of the claims.

[0105] The light-emitting elements according to the embodiments of this disclosure include, for example, the following embodiments: (1) A light-emitting device comprising: a light-emitting element that emits light having a dominant wavelength in the range of 400 nm to 490 nm; and a phosphor that emits light when excited by the light-emitting element, wherein in the emission spectrum of the light-emitting device, the first integral value of the emission intensity in the wavelength range of 600 nm to 780 nm is less than 22.5% of the second integral value of the emission intensity in the wavelength range of 380 nm to 780 nm, and the third integral value of the emission intensity in the wavelength range of 640 nm to 780 nm is less than 7.0% of the second integral value. (2) The light-emitting device according to claim 1, wherein in the emission spectrum of the light-emitting device, the fourth integral value of the emission intensity in the wavelength range of 470 nm to 520 nm is less than 14.4% of the second integral value. (Item 3) The light-emitting device according to Item 1 or 2, wherein in the emission spectrum of the light-emitting device, the sum of the fourth integral value and the third integral value of the emission intensity in the wavelength range of 470 nm to 520 nm is less than 23.0% of the second integral value. (Item 4) The light-emitting device according to any one of Items 1 to 3, wherein the phosphor comprises a first phosphor that emits first light having a peak wavelength in the range of 500 nm to less than 570 nm, and a second phosphor that emits second light having a peak wavelength in the range of 570 nm to 615 nm. (Item 5) The light-emitting device according to any one of items 1 to 4, wherein the phosphor comprises: a first phosphor that emits first light having a chromaticity in a region defined by a first line connecting the first point and the second point, a second line connecting the second point and the third point, a third line connecting the third point and the fourth point, and a fourth line connecting the fourth point and the first point, with the xy chromaticity coordinate (x, y) of the xy chromaticity coordinate of the CIE 1931 chromaticity diagram being (x = 0.23, y = 0.70) as the first point, (x = 0.48, y = 0.70) as the second point, (x = 0.48, y = 0.45) as the third point, and (x = 0.23, y = 0.45) as the fourth point; and a second phosphor that emits second light having an xy chromaticity coordinate different from the xy chromaticity coordinate of the first light.(Item 6) The light-emitting device according to any one of items 1 to 5, wherein the phosphor comprises a first phosphor that emits first light, and a second phosphor that emits second light having xy chromaticity coordinates in the xy chromaticity coordinates of the CIE 1931 chromaticity diagram that are different from the xy chromaticity coordinates of the first light, and the chromaticity coordinate (x, y) is set at (x = 0.48, y = 0.35) as the fifth point, (x = 0.63, y = 0.35) as the sixth point, (x = 0.63, y = 0.53) as the seventh point, and (x = 0.48, y = 0.53) as the eighth point, and the chromaticity is within the region defined by the fifth line connecting the fifth point and the sixth point, the sixth line connecting the sixth point and the seventh point, the seventh line connecting the seventh point and the eighth point, and the eighth line connecting the eighth point and the fifth point. (Clause 7) The light-emitting device according to any one of Claims 1 to 6, wherein the phosphor comprises a first phosphor and a second phosphor, the first phosphor comprising at least one selected from the group consisting of a rare earth aluminate phosphor having a composition represented by the following formula (1A), a rare earth aluminate phosphor having a composition represented by the following formula (1B), a first nitride phosphor having a composition represented by the following formula (1C), and a first oxynitride phosphor having a composition represented by the following formula (1D).

[0106] (Y ａ Lu １－ａ ) ｂ (Al ｃ Ga １－ｃ ) ｄ O １２ : Ce ｕ (1A) (In equation (1A), a, b, c, d, and u are numbers that satisfy 0 ≤ a ≤ 1, 2.8 ≤ b ≤ 3.2, 0 ≤ c ≤ 1, 4.8 ≤ d ≤ 5.2, and 0.009 ≤ u ≤ 0.6, respectively.) (Y ｅ Gd １－ｅ ) ｆ Al ｇ O １２ : Ce ｖ (1B) (In equation (1B), e, f, g, and v are numbers that satisfy 0 ≤ e ≤ 1, 2.8 ≤ f ≤ 3.2, 4.8 ≤ g ≤ 5.2, and 0.009 ≤ v ≤ 0.6, respectively.) La ｈ Y ｉ Gd ｊ Si ６ N ８＋ｋ : Ceｗ (1C) (In formula (1C), h, i, j, k, and w are numbers satisfying 1.5 ≤ h ≤ 3.0, 0 ≤ i ≤ 1.0, 0 ≤ j ≤ 2.0, 2.0 ≤ k ≤ 4.0, and 0 < w ≤ 1.0, respectively.) Si ６－ｍ Al ｍ O ｍ N ８－ｍ : Eu ｘ (1D) (In formula (1D), m and x are numbers satisfying 0 < m ≤ 0.2 and 0 < x ≤ 4.2, respectively. (Item 8) The phosphor includes a first phosphor and a second phosphor, and the second phosphor includes at least one selected from the group consisting of a second nitride phosphor having a composition represented by the following formula (2A) and a second oxynitride phosphor having a composition represented by the following formula (2B). The light-emitting device according to any one of Items 1 to 7.)

[0107] (Ba ｌ Sr ｎ ) ２ Si ５ N ８－ｏ : Eu ｙ (2A) (In formula (2A), l, n, o, and y are numbers satisfying 0.500 ≤ l ≤ 0.995, 0 ≤ n ≤ 0.50, 0 ≤ o ≤ 0.50, 0.9 < l + n + y ≤ 1.0, and 0.001 ≤ y ≤ 0.03, respectively.) M ｐ Si １２－（ｑ＋ｒ） Al ｑ＋ｒ O ｒ N １６－ｒ : Eu ｚ(2B) (In formula (2B), M is at least one element selected from the group consisting of Li, Mg, Ca, Sr, Y and lanthanide elements (excluding La and Ce), and p, q, r, and z are numbers satisfying 0 < p ≤ 2.0, 2.0 ≤ q ≤ 6.0, 0 ≤ r ≤ 1.0, and 0 < z ≤ 1.0, respectively.) (Item 9) The light-emitting device according to any one of items 1 to 8, wherein the first integral value is less than 21.5% of the second integral value. (Item 10) The light-emitting device according to any one of items 1 to 9, wherein the third integral value is less than 6.5% of the second integral value. (Item 11) The light-emitting device according to any one of items 1 to 10, wherein the third integral value is less than 6.0% of the second integral value. (Item 12) The light-emitting device according to item 2, wherein the fourth integral value is less than 12.5% ​​of the second integral value. (Item 13) The light-emitting device according to Item 3, wherein the sum of the fourth integral value and the third integral value is less than 19.5% of the second integral value. (Item 14) The chromaticity of the light emitted by the light-emitting device is such that, in the xy chromaticity coordinates of the CIE 1931 chromaticity diagram, the chromaticity coordinate (x, y) is (x = 0.3100, y = 0.2825) as the first point, (x = 0.3100, y = 0.3484) as the second point, (x = 0.4530, y = 0.4400) as the third point, (x = 0.5000, y = 0.4400) as the fourth point, (x = 0.5000, y = 0.3820) as the fifth point, (x (Item 15) A light-emitting device according to any one of items 1 to 13, wherein the sixth point is defined by a first straight line connecting the first point and the second point, a second straight line connecting the second point and the third point, a third straight line connecting the third point and the fourth point, a fourth straight line connecting the fourth point and the fifth point, a fifth straight line connecting the fifth point and the sixth point, and a sixth straight line connecting the sixth point and the first point. (Item 16) A light-emitting device according to any one of items 1 to 15, wherein the color temperature of the light emitted by the light-emitting device is 5000K or more and 7000K or less. (Item 17) A luminaire equipped with a light-emitting device according to any one of items 1 to 16.

[0108] This application claims priority based on Japanese Patent Application No. 2024-170441, filed on 30 September 2024, and Japanese Patent Application No. 2025-127183, filed on 30 July 2025, and includes the entire contents of these Japanese Patent Applications.

[0109] 10 Package 11 Recess 12, 30 Substrate 16, 36 Light-emitting element 17, 37 Protective element 18A, 18B Lead terminals 19A-19C Bonding wire 20A First phosphor 20B Second phosphor 21 Base material 22 Sealing member 23 Light-transmitting material 24 Wavelength converter 25 Light-transmitting body 33 Adhesive 34 Conductive member 36A Light-emitting surface 40 Lighting control unit 41 Lamp body 42 Outer lens 43 Substrate 44 Optical filter 45 Light guide member 50, 51, 52, 53 Wavelength range 50A Second integral value 51A First integral value 52A Third integral value 53A Fourth integral value 61A, 62A Region 63A First point 63B Second point 63C Third point 63D 4th point 64A 5th point 64B 6th point 64C 7th point 64D 8th point

Claims

1. A light-emitting device comprising: a light-emitting element that emits light having a dominant wavelength in the range of 400 nm to 490 nm; and a phosphor that emits light when excited by the light emitted by the light-emitting element, wherein in the emission spectrum of the light-emitting device, the first integral value of the emission intensity in the wavelength range of 600 nm to 780 nm is less than 22.5% of the second integral value of the emission intensity in the wavelength range of 380 nm to 780 nm, and the third integral value of the emission intensity in the wavelength range of 640 nm to 780 nm is less than 7.0% of the second integral value.

2. The light-emitting device according to claim 1, wherein in the emission spectrum of the light-emitting device, the fourth integral value of the emission intensity in the wavelength range of 470 nm to 520 nm is less than 14.4% of the second integral value.

3. The light-emitting device according to claim 1 or 2, wherein in the emission spectrum of the light-emitting device, the sum of the fourth integral value and the third integral value of the emission intensity in the wavelength range of 470 nm to 520 nm is less than 23.0% of the second integral value.

4. The light-emitting device according to any one of claims 1 to 3, wherein the phosphor comprises a first phosphor that emits first light having a peak wavelength in the range of 500 nm or more and less than 570 nm, and a second phosphor that emits second light having a peak wavelength in the range of 570 nm or more and 615 nm.

5. The light-emitting device according to any one of claims 1 to 4, wherein the phosphor comprises: a first phosphor that emits first light having a chromaticity in a region defined by a first line connecting the first point and the second point, a second line connecting the second point and the third point, a third line connecting the third point and the fourth point, and a fourth line connecting the fourth point and the first point, with the xy chromaticity coordinate (x, y) of the xy chromaticity coordinate of the CIE 1931 chromaticity diagram being (x = 0.23, y = 0.70) as the first point, (x = 0.48, y = 0.70) as the second point, (x = 0.48, y = 0.45) as the third point, and (x = 0.23, y = 0.45) as the fourth point; and a second phosphor that emits second light having an xy chromaticity coordinate different from the xy chromaticity coordinate of the first light.

6. The light-emitting device according to any one of claims 1 to 5, comprising: a first phosphor that emits first light; and a second phosphor that emits second light, having xy chromaticity coordinates in the xy chromaticity coordinates of the CIE 1931 chromaticity diagram that are different from the xy chromaticity coordinates of the first light, and whose chromaticity coordinates (x, y) are defined as (x = 0.48, y = 0.35) as the fifth point, (x = 0.63, y = 0.35) as the sixth point, (x = 0.63, y = 0.53) as the seventh point, and (x = 0.48, y = 0.53) as the eighth point, and the chromaticity being within the region defined by the fifth line connecting the fifth point and the sixth point, the sixth line connecting the sixth point and the seventh point, the seventh line connecting the seventh point and the eighth point, and the eighth line connecting the eighth point and the fifth point.

7. The phosphor includes a first phosphor and a second phosphor, and the first phosphor includes at least one selected from the group consisting of a rare earth aluminate phosphor having a composition represented by the following formula (1A), a rare earth aluminate phosphor having a composition represented by the following formula (1B), a first nitride phosphor having a composition represented by the following formula (1C), and a first oxynitride phosphor having a composition represented by the following formula (1D). The light-emitting device according to any one of claims 1 to 6. (Y ａ Lu １－ａ ) ｂ (Al ｃ Ga １－ｃ ) ｄ O １２ : Ce ｕ (1A) (In formula (1A), a, b, c, d, and u are numbers satisfying 0 ≦ a ≦ 1, 2.8 ≦ b ≦ 3.2, 0 ≦ c ≦ 1, 4.8 ≦ d ≦ 5.2, and 0.009 ≦ u ≦ 0.6, respectively.) (Y ｅ Gd １－ｅ ) ｆ Al ｇ O １２ : Ce ｖ (1B) (In formula (1B), e, f, g, and v are numbers satisfying 0 ≦ e ≦ 1, 2.8 ≦ f ≦ 3.2, 4.8 ≦ g ≦ 5.2, and 0.009 ≦ v ≦ 0.6, respectively.) La ｈ Y ｉ Gd ｊ Si ６ N ８＋ｋ : Ce ｗ (1C) (In formula (1C), h, i, j, k, and w are numbers satisfying 1.5 ≦ h ≦ 3.0, 0 ≦ i ≦ 1.0, 0 ≦ j ≦ 2.0, 2.0 ≦ k ≦ 4.0, and 0 < w ≦ 1.0, respectively.) Si ６－ｍ Al ｍ O ｍ N ８－ｍ : Eu ｘ (1D) (In formula (1D), m and x are numbers satisfying 0 < m ≦ 0.2 and 0 < x ≦ 4.2, respectively.) 8. The light-emitting device according to any one of claims 1 to 7, wherein the phosphor comprises a first phosphor and a second phosphor, and the second phosphor comprises at least one selected from the group consisting of a second nitride phosphor having a composition represented by the following formula (2A) and a second oxynitride phosphor having a composition represented by the following formula (2B). (Ba ｌ Sr ｎ ) ２ Si ５ N ８－ｏ :Eu ｙ (2A) (In equation (2A), l, n, o, and y are numbers that satisfy 0.500 ≤ l ≤ 0.995, 0 ≤ n ≤ 0.50, 0 ≤ o ≤ 0.50, 0.9 < l + n + y ≤ 1.0, and 0.001 ≤ y ≤ 0.03, respectively.) M ｐ Si １２－（ｑ＋ｒ） Al ｑ＋ｒ O ｒ N １６－ｒ :Eu ｚ (2B) (In formula (2B), M is at least one element selected from the group consisting of Li, Mg, Ca, Sr, Y, and lanthanide elements (excluding La and Ce), and p, q, r, and z are numbers satisfying 0 < p ≤ 2.0, 2.0 ≤ q ≤ 6.0, 0 ≤ r ≤ 1.0, and 0 < z ≤ 1.0, respectively.) 9. The light-emitting device according to any one of claims 1 to 8, wherein the first integral value is less than 21.5% of the second integral value.

10. The light-emitting device according to any one of claims 1 to 9, wherein the third integral value is less than 6.5% of the second integral value.

11. The light-emitting device according to any one of claims 1 to 10, wherein the third integral value is less than 6.0% of the second integral value.

12. The light-emitting device according to claim 2, wherein the fourth integral value is less than 12.5% ​​of the second integral value.

13. The light-emitting device according to claim 3, wherein the sum of the fourth integral value and the third integral value is less than 19.5% of the second integral value.

14. The chromaticity of the light emitted by the light-emitting device is determined by the xy chromaticity coordinates of the CIE 1931 chromaticity diagram, where the chromaticity coordinate (x, y) is set as follows: (x = 0.3100, y = 0.2825) as the first point, (x = 0.3100, y = 0.3484) as the second point, (x = 0.4530, y = 0.4400) as the third point, (x = 0.5000, y = 0.4400) as the fourth point, (x = 0.5000, y = 0.3820) as the fifth point, and (x The light-emitting device according to any one of claims 1 to 13, wherein the sixth point is defined by a first straight line connecting the first point and the second point, a second straight line connecting the second point and the third point, a third straight line connecting the third point and the fourth point, a fourth straight line connecting the fourth point and the fifth point, a fifth straight line connecting the fifth point and the sixth point, and a sixth straight line connecting the sixth point and the first point.

15. The light-emitting device according to any one of claims 1 to 14, wherein the color temperature of the light emitted by the light-emitting device is 5000K or more and 7000K or less.

16. The light-emitting device according to any one of claims 1 to 15, wherein the color deviation duv of the light emitted by the light-emitting device is -0.02 or more and 0.02 or less.

17. A luminaire comprising the light-emitting device described in any one of claims 1 to 16.

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