Light-emitting device

Abstract

The present invention provides a light-emitting device that is bright both in scotopic vision and photopic vision and reduces glare to humans. The above light-emitting device includes: a light-emitting element having a main wavelength in the range of 430 nm or more and 500 nm or less, and a phosphor that is excited by the light of the above light-emitting element and has an emission peak wavelength in the range of 507 nm or more and 660 nm or less. The above light-emitting device emits light having a main wavelength in the range of 490 nm or more and 500 nm or less, and the ratio of the light flux in scotopic vision to the light flux in photopic vision, that is, the S / P ratio, is 6.5 or less. The emission intensity at the emission peak wavelength of the above light-emitting element is higher than the emission intensity at the emission peak wavelength of the above phosphor.

Description

Technical Field

[0001] The present invention relates to a light-emitting device. Background Art

[0002] It is known that the visual acuity of the human eye changes between dark and bright places. In photopic vision in a bright environment, colors can be perceived by the operation of cone cells, which are photosensitive cells (visual cells) of the human eye. In scotopic vision in a dark environment, since cone cells do not function, many colors cannot be perceived, but the visual acuity is improved by the operation of rod cells.

[0003] It is known that the peak wavelength of the visual acuity of cone cells that actively operate in bright places is 555 nm, and the peak wavelength of the visual acuity of rod cells that actively operate in dark places is 507 nm. The peak of visual acuity is different between dark and bright places. This phenomenon is known as the Purkinje phenomenon, that is, in bright places, colors on the long-wavelength side look vivid, and in dark places, colors on the short-wavelength side look vivid.

[0004] For example, in Patent Document 1, as an illumination device utilizing the Purkinje phenomenon, a street lamp is proposed that emits white light with high visibility on the sidewalk side for drivers, high visibility for pedestrians, and less color mottling on the lane side and the sidewalk side in a twilight visual environment with an intermediate brightness between dark and bright places. In Patent Document 1, it is considered that the higher the ratio of scotopic vision to photopic vision, that is, the S / P ratio, the higher the visibility of light in a twilight visual environment.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2017-220312 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] However, if the S / P ratio is too high, there is a situation where the human eye feels dark in photopic vision and dazzled in scotopic vision. In addition, in the case of a light-emitting device constituted by combining a light-emitting element and a phosphor, a higher wavelength conversion efficiency of the phosphor is also required.

[0010] An object of one aspect of the present invention is to provide a light-emitting device that is bright both in scotopic vision and photopic vision, reduces glare to humans, and has a higher wavelength conversion efficiency of a phosphor.

[0011] Means for Solving the Problems

[0012] One aspect of the present invention is a light-emitting device, comprising: a light-emitting element having a main wavelength in the range of 430 nm or more and 500 nm or less; and a phosphor that is excited by the light of the light-emitting element and has an emission peak wavelength in the range of 507 nm or more and 660 nm or less, wherein the light-emitting device emits light having a main wavelength in the range of 490 nm or more and 500 nm or less, the ratio of the luminous flux in scotopic vision to the luminous flux in photopic vision, i.e., the S / P ratio, is 6.5 or less, and the luminous intensity at the emission peak wavelength of the light-emitting element is higher than the luminous intensity at the emission peak wavelength of the phosphor.

[0013] Effects of the Invention

[0014] According to one aspect of the present invention, it is possible to provide a light-emitting device that is bright both in scotopic vision and photopic vision and reduces glare to humans. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a graph showing the photopic standard spectral luminous efficiency V(λ) and the scotopic standard spectral luminous efficiency V’(λ).

[0016] Figure 2 It is a graph showing region A in a part of the xy chromaticity coordinate system of the CIE1931 chromaticity diagram.

[0017] Figure 3 It is a schematic cross-sectional view of the light-emitting device according to the first aspect of the present invention.

[0018] Figure 4A It is a schematic top view of the light-emitting device according to the second aspect of the present invention.

[0019] Figure 4B It is a schematic cross-sectional view of the light-emitting device according to the second aspect of the present invention.

[0020] Figure 5 It is a graph showing the emission spectra of the respective phosphors.

[0021] Figure 6 It is a graph showing the emission spectra of the respective phosphors.

[0022] Figure 7 It is a graph showing the emission spectra of the light-emitting devices of Examples 1 to 3.

[0023] Figure 8 It is a graph showing the emission spectra of the light-emitting devices of Examples 4 to 6.

[0024] Figure 9 It is a graph showing the emission spectra of the light-emitting devices of Comparative Examples 1 to 5.

[0025] Figure 10The chromaticity coordinates (x D ,y D ) and the target tonal range (region A).

[0026] Figure 11 The chromaticity coordinates (x D ,y D ) and the target tonal range (region A).

[0027] Figure 12 It is a graph showing the emission spectra of the light-emitting devices of Examples 7 to 9.

[0028] Figure 13 It is a graph showing the emission spectra of the light-emitting devices of Examples 10 to 13.

[0029] Figure 14 It is a graph showing the emission spectra of the light-emitting devices of Comparative Examples 6 to 11.

[0030] Figure 15 The chromaticity coordinates (x D ,y D ) and the target tonal range (region A).

[0031] Figure 16 The chromaticity coordinates (x D ,y D ) and the target tonal range (region A). DETAILED DESCRIPTION

[0032] The light-emitting device of the present invention is described below based on one embodiment. However, the embodiment shown below is an example for concretizing the technical concept of the present invention, and the present invention is not limited to the light-emitting device below. It should be noted that the relationship between color names and chromaticity coordinates, and the relationship between the wavelength range of light and the color name of monochromatic light are based on JIS Z 8110. In addition, regarding the content of each component in the composition, when there are multiple substances equivalent to each component in the composition, unless otherwise specified, it refers to the total amount of the multiple substances present in the component.

[0033] Light-emitting device

[0034] The light-emitting device includes a light-emitting element having a main wavelength in the range of 430 nm or more and 500 nm or less, and a phosphor that is excited by the light of the light-emitting element and has a light-emission peak wavelength in the range of 507 nm or more and 660 nm or less. The light-emitting device emits light having a main wavelength in the range of 490 nm or more and 500 nm or less, and the ratio of the luminous flux in scotopic vision to the luminous flux in photopic vision, that is, the S / P ratio, is 6.5 or less. The luminous intensity at the light-emission peak wavelength of the light-emitting element is higher than the luminous intensity at the light-emission peak wavelength of the phosphor.

[0035] The main wavelength of the light-emitting element refers to the wavelength at which a straight line connecting the chromaticity coordinates (x = 0.3333, y = 0.3333) of white light in the CIE (International Commission on Illumination: Commission Internationale de l’Eclairage) 1931 chromaticity diagram and the chromaticity coordinates (x E , y E ) of the emission color of the light-emitting element intersects the spectral locus at the extension of the straight line. The main wavelength of the light-emitting device refers to the wavelength at which a straight line connecting the chromaticity coordinates (x = 0.3333, y = 0.3333) of white light in the CIE 1931 chromaticity diagram and the chromaticity coordinates (x D , y D ) of the emission color of the light-emitting device intersects the spectral locus at the extension of the straight line.

[0036] The light-emitting device includes a light-emitting element having a main wavelength in the blue to blue-green wavelength range and a phosphor having a light-emission peak wavelength in the green, yellow-green, yellow, yellow-red, and red wavelength ranges. The light-emitting device emits light having a main wavelength in the blue-green to green wavelength range. It is known that the higher the ratio of the luminous flux in scotopic vision to the luminous flux in photopic vision, that is, the S / P ratio, the higher the visibility of a person. Figure 1 is a graph showing the photopic standard spectral luminous efficiency V(λ) and the scotopic standard spectral luminous efficiency V’(λ). As Figure 1As shown, the peak wavelength of the photopic standard spectral luminous efficiency V(λ) is 555 nm, and the peak wavelength of the scotopic standard spectral luminous efficiency V’(λ) is 507 nm. The peak of visual acuity is different in the dark and in the light. It is known that the peak wavelengths of the visual acuity of the human eye are different in the light and in the dark. Therefore, for the human eye, due to the twilight phenomenon, the colors on the long-wavelength side look vivid in the light, and the colors on the short-wavelength side look vivid in the dark. For a light-emitting device that emits light having a dominant wavelength in the wavelength range of blue-green to green, if the S / P ratio is increased to improve visibility, when viewed in the dark, the colors on the short-wavelength side become too vivid and sometimes cause glare. The light-emitting device according to an embodiment of the present invention sets the S / P ratio to 6.5 or less even when emitting light having a dominant wavelength in the wavelength range of blue to green including blue-green, thereby reducing the difference between the light flux in the dark and the light flux in the light, looking bright both in scotopic vision and in photopic vision, maintaining excellent visibility, and being able to reduce the glare felt by a person.

[0037] The ratio of the light flux in scotopic vision to the light flux in photopic vision of the light emitted from the light-emitting device, that is, the S / P ratio, is 6.5 or less, preferably 6.0 or less, preferably 2.0 or more, more preferably 3.0 or more, and further preferably 4.0 or more. The S / P ratio of the light emitted from the light-emitting device is 6.5 or less. By reducing the difference between the light flux in scotopic vision and the light flux in photopic vision, even in a light-emitting device that emits light having a dominant wavelength in the wavelength range of blue to green including blue-green, it is possible to emit light that maintains excellent visibility and looks bright both in scotopic vision and in photopic vision, and reduces the glare felt by a person both in scotopic vision and in photopic vision. The dominant wavelength, light flux, chromaticity coordinates in the xy chromaticity coordinate system of the CIE1931 chromaticity diagram, and radiant flux of the light emitted from the light-emitting device or the light-emitting element can be measured using an optical measurement system combining a spectrophotometric device (for example, PMA-11, manufactured by Hamamatsu Photonics K.K.) and an integrating sphere. In addition, the ratio of the light flux in the dark to the light flux in the light, that is, the S / P ratio, can be calculated based on the calculation formula (i).

[0038] When V(λ) is the spectral luminous efficiency in photopic vision (photopic standard spectral luminous efficiency) and V’(λ) is the spectral luminous efficiency in scotopic vision (scotopic standard spectral luminous efficiency), the following S / P ratio (R SP ) can be calculated based on the calculation formula (i).

[0039]

Mathematical formula 1

[0040]

[0041] In calculation formula (i), constant K is 6831 lm / W, constant K' is 1700 hn / W, and Φe(λ) is the radiant flux (spectral total radiant flux) of each light emitting device of the embodiment and comparative example.

[0042] For the light-emitting device, it is preferred to emit light whose chromaticity coordinates (x, y) are within the following area in the xy chromaticity coordinate system of the CIE1931 chromaticity diagram: the area is the area defined by (x=0.0082, y=0.5384) as the first point, (x=0.0454, y=0.2950) as the second point, (x=0.2000, y=0.3200) as the third point, (x=0.2000, y=0.4000) as the fourth point, the first straight line connecting the above-mentioned first point and the above-mentioned second point, the second straight line connecting the above-mentioned second point and the above-mentioned third point, the third straight line connecting the above-mentioned third point and the above-mentioned fourth point, and the fourth straight line connecting the above-mentioned fourth point and the above-mentioned first point. Figure 2 represents a portion of the xy chromaticity coordinate system of the CIE 1931 chromaticity diagram. The light emitting device preferably emits light by connecting Figure 2 The light emitting device emits light in the area A surrounded by the straight lines between the first and second points, the second and third points, the third and fourth points, and the fourth and first points. Figure 2 The light in region A has a dominant wavelength within a range of 490 nm to 500 nm, and exhibits a blue to green color including cyan.

[0043] In the emission spectrum of the light-emitting device, the ratio Ib / Ia of the integral value Ib in the wavelength range of 380 nm or more and 531 nm or less to the integral value Ia in the wavelength range of 380 nm or more and 780 nm or less is preferably in the range of 0.6 or more and 0.95 or less, more preferably in the range of 0.65 or more and 0.94 or less, still more preferably in the range of 0.70 or more and 0.93 or less, and particularly preferably in the range of 0.75 or more and 0.92 or less. In the emission spectrum of the light-emitting device, if the ratio Ib / Ia of the above integral values is in the range of 0.6 or more and 0.95 or less, light having a main wavelength in the wavelength range of blue to green including blue-green is emitted from the light-emitting device, and it is possible to emit light with excellent visibility that appears bright both in scotopic vision and photopic vision, and with reduced glare perceived by a person both in scotopic vision and photopic vision. The emission spectrum of the light-emitting device, the integral value Ia in the wavelength range of 380 nm or more and 780 nm or less in the measured emission spectrum, the integral value Ib in the wavelength range of 380 nm or more and 531 nm or less, the emission intensity b of the phosphor at the emission peak wavelength in the emission spectrum of the light-emitting device described below, and the emission intensity a of the light-emitting element at the emission peak wavelength in the emission spectrum of the light-emitting device can be measured using an optical measurement system combining a spectrophotometric device (e.g., PMA-11, manufactured by Hamamatsu Photonics K.K.) and an integrating sphere. The ratio Ib / Ia of the integral values can be obtained from the measured integral values Ia and Ib. The ratio a / b of the emission intensities described below can be obtained from the measured emission intensity a of the light-emitting element at the emission peak wavelength and the emission intensity b of the phosphor at the emission peak wavelength in the emission spectrum of the light-emitting device.

[0044] For the light-emitting device, in the emission spectrum of the light-emitting device, the emission intensity a of the light-emitting element at the emission peak wavelength is higher than the emission intensity b of the phosphor at the emission peak wavelength. Since the emission intensity a of the light-emitting element at the emission peak wavelength is higher than the emission intensity b of the phosphor at the emission peak wavelength in the light-emitting device, even when light having a main wavelength in the wavelength range of blue to green including blue-green is emitted, the S / P ratio can be set to 6.5 or less, the difference between the light flux in the dark and the light flux in the light can be reduced, it appears bright both in scotopic vision and photopic vision, excellent visibility is maintained, and the glare perceived by a person can be reduced.

[0045] In the emission spectrum of the light-emitting device, the ratio a / b of the emission intensity a of the emission peak wavelength of the light-emitting element to the emission intensity b of the emission peak wavelength of the phosphor is preferably 3.0 or more. In the emission spectrum of the light-emitting device, if the ratio a / b of the emission intensity a of the emission peak wavelength of the light-emitting element to the emission intensity b of the emission peak wavelength of the phosphor is 3.0 or more, light having a main wavelength in the range of 490 nm or more and 500 nm or less is emitted from the light-emitting device, the S / P ratio is 6.5 or less, and light that maintains excellent visibility that appears bright both in scotopic vision and photopic vision and reduces the glare felt by humans both in scotopic vision and photopic vision can be emitted. In the emission spectrum of the light-emitting device, if the ratio a / b of the emission intensities is less than 3.0, for the light emitted from the light-emitting device, the emission intensity of the emission peak wavelength of the light-emitting element may become lower than the emission intensity of the emission peak wavelength of the phosphor, and the visibility that appears bright cannot be maintained both in scotopic vision and photopic vision. In the emission spectrum of the light-emitting device, the ratio a / b of the emission intensity a of the emission peak wavelength of the light-emitting element is more preferably 3.5 or more, and may also be 4.0 or more. In the emission spectrum of the light-emitting device, the ratio a / b of the emission intensity a of the emission peak wavelength of the light-emitting element to the emission intensity b of the emission peak wavelength of the phosphor may be 50 or less, or may also be 45 or less.

[0046] The light-emitting device preferably emits light such that the ratio Fb / Fa of the radiant flux Fb of the light-emitting device to the radiant flux Fa of the light-emitting element is 0.75 or more. If the ratio Fb / Fa of the radiant flux Fb of the light emitted from the light-emitting device to the radiant flux Fa of the light-emitting element used in the light-emitting device is 0.75 or more, light that exhibits a blue to green emission color including blue-green while maintaining the radiant energy of the emission of the light-emitting element, reduces the glare felt by humans, and appears bright both in scotopic vision and photopic vision and maintains excellent visibility is emitted from the light-emitting device. The light-emitting device more preferably emits light such that the ratio Fb / Fa of the radiant fluxes is 0.76 or more, further preferably emits light such that the ratio Fb / Fa of the radiant fluxes is 0.78 or more, and particularly preferably emits light such that the ratio Fb / Fa of the radiant fluxes is 0.80 or more. The ratio Fb / Fa of the radiant flux Fb of the light-emitting device to the radiant flux Fa of the light-emitting element is usually 1 or less, may be 0.99 or less, or may also be 0.98 or less.

[0047] Light-emitting element

[0048] The light-emitting element can be used, for example, as one using a composition formula of In X Al Y Ga 1-X-YA light-emitting diode (LED) chip or a laser diode (LD) chip of a nitride-based semiconductor represented by N(0≤X, 0≤Y, X+Y≤1), and an LED chip is preferably used.

[0049] The light-emitting element has a peak wavelength in the range of 430 nm or more and 500 nm or less. The peak wavelength of the light emitted from the light-emitting element is preferably in the range of 440 nm or more and 500 nm or less, and more preferably in the range of 450 nm or more and 500 nm or less.

[0050] The light-emitting element preferably has an emission peak wavelength in the range of 380 nm or more and 500 nm or less, more preferably in the range of 390 nm or more and 495 nm or less, further preferably in the range of 400 nm or more and 490 nm or less, and particularly preferably in the range of 420 nm or more and 490 nm or less.

[0051] The light-emitting element is provided with a p electrode and an n electrode. The p electrode and the n electrode of the light-emitting element can be formed on the same side surface of the light-emitting element, or can be provided on different side surfaces. The light-emitting element can be flip-chip mounted.

[0052] Phosphor

[0053] The phosphor is excited by the light of the light-emitting element and has an emission peak wavelength in the range of 507 nm or more and 660 nm or less. The emission peak wavelength of the phosphor is preferably in the range of 510 nm or more and 655 nm or less, and more preferably in the range of 520 nm or more and 650 nm or less.

[0054] The full width at half maximum of the phosphor is preferably in the range of 45 nm or more and 120 nm or less. The full width at half maximum (FWHM) of the phosphor refers to the wavelength width of the emission spectrum that exhibits 50% of the maximum emission intensity in the emission spectrum of the phosphor. The full width at half maximum of the phosphor is more preferably in the range of 48 nm or more and 110 nm or less, and further preferably in the range of 50 nm or more and 105 nm or less.

[0055] The phosphor preferably includes at least one phosphor selected from the following phosphors: (I) a rare earth aluminate phosphor having a composition containing Ce, Al, at least one element Ln selected from Y, La, Lu, Gd, and Tb, and optionally at least one element selected from Ga and Sc; (II) a β-sialon phosphor having a composition containing Si, Al, O, N, and Eu; (III) a halosilicate phosphor having a composition containing Ca, Eu, Mg, Si, O, and at least one halogen element selected from F, Cl, and Br; and (IV) a nitride phosphor having a composition containing Ca, Eu, Si, Al, N, and optionally Sr. The light-emitting device emits light having a main wavelength in the range of 490 nm or more and 500 nm or less by including a light-emitting element having a main wavelength in the range of 430 nm or more and 500 nm or less and at least one phosphor selected from rare earth aluminate phosphors, β-sialon phosphors, halosilicate phosphors, and nitride phosphors.

[0056] The phosphor preferably contains at least one phosphor selected from a rare earth aluminate phosphor having the composition represented by the following formula (1), a halosilicate phosphor having the composition represented by the following formula (2), a β-sialon phosphor having the composition represented by the following formula (3), and a nitride phosphor having the composition represented by the following formula (4). The phosphor may contain two or more phosphors having the compositions represented by the following formulas (1) to (4).

[0057] (Y, Lu, Gd)3(Al, Ga)5O 12 : Ce (1)

[0058] (Ca, Sr, Ba)8MgSi4O 16 (F, Cl, Br)2: Eu (2)

[0059] Si 6-z Al z O z N 8-z : Eu, 0 ≤ z ≤ 4.2 (3)

[0060] (Sr, Ca)AlSiN3: Eu (4)

[0061] In this specification, in the compositional formula representing the phosphor composition, the multiple elements listed separated by a comma (,) mean that at least one of these multiple elements is included in the composition, and two or more of the multiple elements may be included in combination. Further, in the formula representing the composition of the phosphor, the elements and their molar ratios constituting the host crystal are indicated before the colon (:), and the activating element is indicated after the colon (:). "Molar ratio" means the molar amount of an element in 1 mole of the phosphor composition.

[0062] The rare earth aluminate phosphor may have a composition represented by the following formula (1a).

[0063] (Y 1-a-b-c Lu a Gd b )3(Al 1-c Ga c )5O 12 :Ce d (1a)

[0064] In formula (1a), a, b, c, and d are numbers satisfying 0 ≤ a ≤ 1.0, 0 ≤ b ≤ 1.0, 0 ≤ a + b ≤ 1.0, 0 ≤ c ≤ 1.0, and 0 < d ≤ 0.022. In formula (1a), d can be 0.001 ≤ d ≤ 0.021.

[0065] The halosilicate phosphor may have a composition represented by the following formula (2a).

[0066] (Ca 1-e-f Sr e Ba f )8MgSi4O 16 (F 1-g-h Cl g Br h :Eu i (2a)

[0067] In formula (2a), e, f, g, h, and i are numbers satisfying 0 ≤ e ≤ 1.0, 0 ≤ f ≤ 1.0, 0 ≤ e + f ≤ 1.0, 0 ≤ g ≤ 1.0, 0 ≤ h ≤ 1.0, 0 ≤ g + h ≤ 1.0, and 0 < i ≤ 1.0. In formula (2a), i can be a number satisfying 0.01 ≤ i ≤ 0.9. In formula (2a), g can be a number satisfying 0 < g ≤ 1.0.

[0068] The β - sialon phosphor may have a composition represented by the following formula (3a).

[0069] Si 6-z Al z O z N 8-z :Eu j (3a)

[0070] In formula (3a), j and z are numbers satisfying 0 < j ≤ 1.0 and 0 < z ≤ 4.2. In formula (3a), j can be a number satisfying 0.01 ≤ j ≤ 0.9.

[0071] The nitride phosphor may have a composition represented by the following formula (4a).

[0072] (Sr 1-k Cak )AlSiN3:Eu m (4a)

[0073] In formula (4a), k and m are numbers satisfying 0 ≤ k ≤ 1.0 and 0 < m ≤ 1.0. In formula (4a), m can be a number satisfying 0.0001 ≤ m ≤ 0.9.

[0074] The average particle diameter of the phosphor is preferably in the range of 2 μm or more and 40 μm or less, more preferably in the range of 3 μm or more and 30 μm or less, and still more preferably in the range of 5 μm or more and 25 μm or less. The larger the particle diameter of the phosphor particles, the more efficiently the light emitted from the light-emitting element can be wavelength-converted, and the more the light extraction efficiency can be improved. On the other hand, if the phosphor particles are too large, the workability in the manufacturing process of the light-emitting device is reduced. The average particle diameter of the phosphor particles can be measured by the Fisher Sub-Sieve Sizer method (hereinafter, also referred to as the "FSSS method"). The FSSS method is a kind of air permeability method, which is a method of measuring the specific surface area by using the flow resistance of air and mainly obtaining the particle diameter of primary particles. The average particle diameter measured by the FSSS method is the Fisher Sub-Sieve Sizer's Number.

[0075] Wavelength conversion member

[0076] The light-emitting device preferably includes a wavelength conversion member containing a phosphor and a light-transmitting material. The wavelength conversion member preferably contains the phosphor in the range of 0.5 part by mass or more and 65 parts by mass or less with respect to 100 parts by mass of the light-transmitting material. The light-emitting device includes a wavelength conversion member containing a phosphor excited by the light emission of the light-emitting element, and the wavelength conversion member is disposed on the light-emitting side of the light of the light-emitting element, so that the light from the light-emitting element can be efficiently wavelength-converted by the phosphor contained in the wavelength conversion member. The wavelength conversion member can contain the phosphor in an amount of 1 part by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the light-transmitting material.

[0077] Light-transmitting material

[0078] Examples of the light-transmitting material include at least one selected from resins, glass, and inorganic substances. The resin is preferably at least one selected from epoxy resins, silicone resins, phenolic resins, and polyimide resins. Examples of the inorganic substance include at least one selected from aluminum oxide and aluminum nitride. In the wavelength conversion member, in addition to the phosphor and the light-transmitting material, a filler, a colorant, and a light diffusion material may be included as needed. Examples of the filler include silica, barium titanate, titanium oxide, and aluminum oxide. The content of other components other than the phosphor and the light-transmitting material contained in the wavelength conversion member, based on the total content of the other components, may be in the range of 0.01 part by mass or more and 50 parts by mass or less, may be in the range of 0.1 part by mass or more and 45 parts by mass or less, or may be in the range of 0.5 part by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the light-transmitting material.

[0079] The light-emitting device of the first mode

[0080] An example of the light-emitting device will be described with reference to the drawings. Figure 3 is a cross-sectional schematic view of the light-emitting device 100 of the first mode. The light-emitting device 100 includes: a light-emitting element 11 having a main wavelength in the range of 430 nm or more and 500 nm or less, a wavelength conversion member 31 including at least one phosphor 21 that emits light when excited by the light from the light-emitting element 11, and a molded body 41. The molded body 41 is integrally formed by integrally molding a first lead 51, a second lead 52, and a resin portion 42 containing a resin. The molded body 41 forms a recess having a bottom surface and a side surface, and the light-emitting element 11 is placed on the bottom surface of the recess. The light-emitting element 11 has a pair of positive and negative electrodes, and the pair of positive and negative electrodes are electrically connected to the first lead 51 and the second lead 52 via wires as conductive members 61, respectively. The light-emitting element 11 is covered with the wavelength conversion member 31. The wavelength conversion member 31 includes a phosphor 21 and a light-transmitting material. The phosphor 21 has at least one emission peak wavelength in a specific wavelength range when excited by the light from the light-emitting element 11. The wavelength conversion member 31 may also include two or more phosphors 21 having different emission peak wavelengths. A part of the first lead 51 and the second lead 52 connected to the pair of positive and negative electrodes of the light-emitting element 11 is exposed toward the outside of the molded body 41. Through the first lead 51 and the second lead 52, power is supplied from the outside of the light-emitting device 100, and the light-emitting device 100 can emit light.

[0081] The wavelength conversion member 31 in the light-emitting device 100 of the first mode preferably includes a phosphor 21 and a light-transmitting material, and the light-transmitting material is a resin. Examples of the resin as the light-transmitting material used in the wavelength conversion member 31 used in the light-emitting device 100 of the first mode include the resins used in the above-mentioned light-transmitting materials.

[0082] The manufacturing method of the light-emitting device of the first mode

[0083] An example of a method for manufacturing a light-emitting device of the first mode will be described. It should be noted that for detailed information, reference can also be made to, for example, the disclosure of Japanese Patent Application Laid-Open No. 2010-062272. The method for manufacturing a light-emitting device preferably includes: a step of preparing a molded body, a step of arranging light-emitting elements, a step of arranging a composition for a wavelength conversion member, and a step of forming a resin encapsulation. When using an aggregated molded body having a plurality of recesses as the molded body, after the step of forming the resin encapsulation, a singulation step of separating according to the resin encapsulation of each unit region may also be included.

[0084] In the step of preparing the molded body, a plurality of leads are integrally formed using a thermosetting resin or a thermoplastic resin to prepare a molded body having recesses, the recesses having side surfaces and bottom surfaces. The molded body may be a molded body composed of an aggregated substrate including a plurality of recesses.

[0085] In the step of arranging the light-emitting elements, the light-emitting elements are arranged on the bottom surfaces of the recesses of the molded body, and the positive and negative electrodes of the light-emitting elements are connected to the first lead and the second lead through wires.

[0086] In the step of arranging the composition for the wavelength conversion member, the composition for the wavelength conversion member is arranged in the recesses of the molded body.

[0087] In the step of forming the resin encapsulation, the composition for the wavelength conversion member arranged in the recesses of the molded body is cured to form a resin encapsulation, thereby manufacturing a light-emitting device. When using a molded body composed of an aggregated substrate including a plurality of recesses, after the step of forming the resin encapsulation, in the singulation step, each resin encapsulation of each unit region of the aggregated substrate having a plurality of recesses is separated to manufacture individual light-emitting devices. As described above, it is possible to manufacture Figure 3 the light-emitting device of the first mode shown.

[0088] The light-emitting device of the second mode

[0089] Figure 4A is a top view schematic diagram of the light-emitting device 200 of the second mode, Figure 4B is Figure 4ACross-sectional schematic view of the IIA-IIA' line of the light-emitting device 200 shown. The light-emitting device 200 includes: a light-emitting element 12 having a main wavelength in the range of 430 nm or more and 500 nm or less, and a wavelength conversion body 34 including a wavelength conversion member 32 and a light-transmitting body 33. The wavelength conversion member 32 includes at least one phosphor that is excited by the light from the light-emitting element 12 and emits light. The light-transmitting body 33 is integrally formed with the wavelength conversion member 32. The light-emitting element 12 is flip-chip mounted on the substrate 72 via bumps as conductive members 62. The wavelength conversion member 32 of the wavelength conversion body 34 is provided on the light-emitting surface of the light-emitting element 12 via an adhesive layer 82. The sides of the light-emitting element 12 and the wavelength conversion body 34 are covered with a light-reflecting covering member 92. The wavelength conversion member 32 includes a phosphor that is excited by the light from the light-emitting element 12 and has at least one emission peak wavelength in a specific wavelength range. The wavelength conversion member 32 may include two or more phosphors having different wavelength ranges of the emission peak wavelength. The light-emitting element 12 can receive power supply from the outside of the light-emitting device 200 via wirings formed on the substrate 72 and the conductive members 62, and cause the light-emitting device 200 to emit light. The light-emitting device 200 may include semiconductor elements 13 such as protection elements for preventing the light-emitting element 12 from being damaged due to an excessive applied voltage. The covering member 92 is provided, for example, so as to cover the semiconductor element 13. Hereinafter, each member used in the light-emitting device of the second embodiment will be described. Note that, for details, reference can also be made to the disclosure of Japanese Patent Application Laid-Open No. 2014-112635, for example.

[0090] Substrate of the light-emitting device of the second embodiment

[0091] The substrate is preferably made of an insulating material that does not easily transmit light from the light-emitting element or external light. Examples of the material of the substrate include ceramics such as alumina and aluminum nitride, phenolic resin, epoxy resin, polyimide resin, bismaleimide triazine resin (BT resin), polyphthalamide (PPA) resin, and the like. Since ceramics have high heat resistance, they are preferably used as the material of the substrate.

[0092] Wavelength conversion body of the light-emitting device of the second embodiment

[0093] Wavelength conversion member

[0094] The wavelength conversion body preferably includes a wavelength conversion member containing a phosphor and a light-transmitting material, and more preferably further includes a light-transmitting body on which the wavelength conversion member is disposed.

[0095] The wavelength conversion member preferably includes a phosphor and at least one of the above-mentioned light-transmitting materials selected from resins, glass, and inorganic substances (such as alumina), and is formed into a sheet or plate shape. The wavelength conversion member can be a single layer or two or more layers. In the wavelength conversion member, in addition to the phosphor and the light-transmitting material, fillers, colorants, and light diffusion materials can also be included as needed.

[0096] The wavelength conversion member can use a ceramic composite obtained by sintering a phosphor and the above-mentioned glass or inorganic substance as the light-transmitting material, and is formed into a sheet or plate shape for use as the wavelength conversion member.

[0097] Light-transmitting body

[0098] The light-transmitting body can use a plate-shaped body made of a light-transmitting material such as glass or resin. Examples of glass include borosilicate glass and quartz glass. Examples of resin include silicone resin and epoxy resin. The thickness of the light-transmitting body only needs to be such that the mechanical strength during the manufacturing process is not reduced and it can sufficiently support the phosphor layer. The light-transmitting body can contain a diffusing agent. If the light-transmitting body contains a diffusing agent, color unevenness and brightness unevenness of the light emitted from the light-emitting device can be suppressed. The diffusing agent can use at least one selected from titanium oxide, barium titanate, alumina, and silicon oxide.

[0099] Adhesive layer

[0100] The adhesive layer is interposed between the light-emitting element and the wavelength conversion member to fix the light-emitting element and the wavelength conversion member. The adhesive constituting the adhesive layer is preferably made of a material that can optically connect the light-emitting element and the wavelength conversion member. As the material constituting the adhesive layer, at least one resin selected from epoxy resin, silicone resin, phenolic resin, and polyimide resin is preferred.

[0101] Semiconductor element

[0102] Semiconductor elements provided in the light-emitting device as needed, for example, include transistors for controlling the light-emitting element and protection elements for suppressing damage and performance degradation of the light-emitting element caused by the application of an excessive voltage. Examples of the protection element include a Zener Diode.

[0103] Coating member

[0104] As the material of the coating member, an insulating material is preferably used. More specifically, examples thereof include phenolic resin, epoxy resin, bismaleimide triazine resin (BT resin), polyphthalamide (PPA) resin, and silicone resin. Colorants and fillers may be added to the coating member as needed. As the filler, an oxide containing at least one element selected from yttrium, zirconium, aluminum, titanium, magnesium, and silicon is preferred. Considering reflectivity and workability, the amount of the filler contained in the coating member is preferably in the range of 10 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the resin.

[0105] Conductive member

[0106] As the conductive member, bumps can be used. As the material of the bumps, Au or its alloy can be used. As other conductive members, eutectic solder (Au-Sn), Pb-Sn, lead-free solder, etc. can be used. The light-emitting device may include underfill in order to protect the light-emitting element, semiconductor element, and conductive member disposed on the substrate from dust, moisture, and external force. As the material of the underfill, for example, silicone resin, epoxy resin, and urea resin can be cited. The underfill may contain colorants, light diffusing agents, and fillers in these resins as needed.

[0107] Manufacturing method of the light-emitting device of the second mode

[0108] An example of the manufacturing method of the light-emitting device of the second mode will be described. It should be noted that for detailed information, reference can also be made to the disclosures of Japanese Unexamined Patent Application Publication No. 2014-112635 or Japanese Unexamined Patent Application Publication No. 2017-117912, for example. The manufacturing method of the light-emitting device preferably includes a step of disposing a light-emitting element, a step of disposing a semiconductor element as needed, a step of forming a wavelength conversion body including a wavelength conversion member, a step of bonding the light-emitting element and the wavelength conversion member, and a step of forming a coating member. In the case where an assembled substrate on which a plurality of light-emitting elements, wavelength conversion members, and semiconductor elements are disposed on one substrate is formed, a singulation step of separating by resin encapsulation for each unit region may also be included.

[0109] Step of disposing the light-emitting element

[0110] In the step of disposing the light-emitting element, the light-emitting element is disposed and mounted on the substrate. In the case of using an assembled substrate, a plurality of light-emitting elements are disposed on the assembled substrate. In addition, a semiconductor element may be disposed as needed between the light-emitting element and an adjacent light-emitting element in either the row or column direction of the disposed light-emitting elements. The light-emitting element and the semiconductor element are, for example, flip-chip mounted on the substrate.

[0111] Step of forming a wavelength conversion body including a wavelength conversion member

[0112] In the process of forming a wavelength conversion body including a wavelength conversion member, the wavelength conversion member can be obtained by forming a plate-like, sheet-like or layered wavelength conversion member on one surface of a light-transmitting body by a printing method, an adhesion method, a compression molding method, or an electrodeposition method. For example, in the printing method, a composition of a wavelength conversion member containing a phosphor and a resin serving as a binder or a solvent can be printed on one surface of the light-transmitting body to form a wavelength conversion body including the wavelength conversion member.

[0113] Adhesion process of a light-emitting element and a wavelength conversion member

[0114] In the adhesion process of a light-emitting element and a wavelength conversion member, the wavelength conversion member is opposed to the light-emitting surface of the light-emitting element, and a wavelength conversion body including the wavelength conversion member and the light-transmitting body is joined to the light-emitting element through an adhesion layer. In a preferred mode, the joint surface of the wavelength conversion body with the light-emitting element, that is, the joint surface of the wavelength conversion member with the light-emitting element is preferably larger than the joint surface of the light-emitting element.

[0115] Formation process of a covering member

[0116] In the formation process of the covering member, the sides of the light-emitting element and the wavelength conversion body including the wavelength conversion member and the light-transmitting body, other than the light-emitting surface, are covered with a composition for the covering member, and a covering member is formed on the sides of the light-emitting element and the wavelength conversion body other than the light-emitting surface. When a plurality of light-emitting elements and semiconductor elements are arranged on a collective substrate and the wavelength conversion bodies are joined to the respective light-emitting elements, a composition for the covering member is filled between the light-emitting elements and the wavelength conversion bodies and the semiconductor elements. The covering member is used to reflect the light emitted from the light-emitting element, and it is formed in such a way as to cover the sides without covering the light-emitting surface of the wavelength conversion body and to embed the semiconductor element.

[0117] When a plurality of light-emitting elements, wavelength conversion bodies, and semiconductor elements are arranged on a collective substrate, the covering member and the collective substrate are cut in such a way that each unit area includes one light-emitting element, one wavelength conversion body, and one semiconductor element, so as to be separated by each unit area, and individual light-emitting devices are manufactured. The resin encapsulation of each unit area is separated to manufacture individual light-emitting devices. As described above, it is possible to manufacture Figure 4A and Figure 4B the light-emitting device of the second mode shown.

[0118] Examples

[0119] Hereinafter, the present invention will be specifically described by way of examples. The present invention is not limited to these examples.

[0120] Phosphor

[0121] Phosphors 1 to 8 used in each of the light-emitting devices of the examples and comparative examples are shown in Table 1. Phosphor 1 (BSiON) is a nitride phosphor having the composition represented by BaSi₂O₂N₂:Eu. Phosphor 2 (SAE) is an aluminate phosphor having the composition represented by Sr₄Al 14 O 25 :Eu. Phosphor 3 (LAG) is a rare-earth aluminate phosphor having the composition represented by the above formula (1). Phosphor 4 (β-sialon) is a β-sialon phosphor having the composition represented by the above formula (3). Phosphor 5 (chlorosilicate) is a kind of halosilicate phosphor having the composition represented by the above formula (2) and having a composition containing Cl. Phosphor 6 (SCASN-1), phosphor 7 (SCASN-2) having a molar ratio of the composition different from that of phosphor 6, and phosphor 8 (CASN-1) are nitride phosphors having the composition represented by the above formula (4). The method for evaluating each phosphor is described below, and the evaluation results are shown in Table 1.

[0122] Evaluation of Phosphors

[0123] Luminescence Characteristics

[0124] The luminescence characteristics of each phosphor were measured. Regarding the luminescence characteristics of the phosphor, light with an excitation light wavelength of 450 nm was irradiated to each phosphor using a quantum efficiency measuring device (QE-2000, manufactured by Otsuka Electronics Co., Ltd.), and the luminescence spectrum at room temperature (25 °C ± 5 °C) was measured. From the luminescence spectra of the respective phosphors, the chromaticity coordinates (x, y) in the chromaticity coordinate system in the CIE chromaticity diagram were determined for each phosphor. The luminescence spectra of each phosphor are shown in Figure 5 and Figure 6 . The emission peak wavelength (nm) and the full width at half maximum were determined from the obtained luminescence spectra of the respective phosphors.

[0125] Average Particle Size

[0126] For each phosphor, the average particle size was measured by the FSSS method using a Fisher Sub-Sieve Sizer Model 95 (manufactured by Fisher Scientific).

[0127] Composition Analysis

[0128] For the nitride phosphors having the composition represented by the formula (4) of phosphors 6 to 8, Sr, Eu, and Ca in the composition were analyzed using an ICP-AES device (manufactured by Perkin Elmer) and an ion chromatography system (manufactured by DIONEX Japan). The molar ratios of Sr, Eu, and Ca were calculated when the total of Sr, Eu, and Ca was set to 1 mole.

[0129]

Table 1

[0130]

[0131] As Figure 5 and Figure 6 shown, the phosphor 3 (LAG) having the composition shown in formula (1), the phosphor 4 (β-sialon) having the composition shown in formula (3), the phosphor 5 (chlorosilicate) having the composition shown in formula (2), and the phosphors 6, 7, and 8 (SCASN-1, SCASN-2, CASN-1) having the composition shown in formula (4) have emission peak wavelengths in the wavelength range of 507 nm or more, which is the peak wavelength of the spectral luminous efficacy of vision in the dark.

[0132] As Figure 5 shown, the phosphor 1 (BSiON) as a nitride phosphor and the phosphor 2 (SAE) as an aluminate phosphor have emission peak wavelengths in the wavelength range of 507 nm or less, which is the peak wavelength of the spectral luminous efficacy of vision in scotopic vision.

[0133] Example 1

[0134] A light-emitting device of the first mode was manufactured. A molded body having a recess was prepared. The recess had a first lead, a second lead, a bottom surface, and a side surface. A light-emitting element using a nitride-based semiconductor having a peak wavelength of 483 nm was prepared, and the light-emitting element was disposed on the bottom surface of the recess and connected to the first lead and the second lead by wires. A wavelength-converting member composition containing 30 parts by mass of the phosphor 3 (LAG) having the composition shown in formula (1) with respect to 100 parts by mass of a silicone resin as a light-transmitting material was prepared, and the wavelength-converting member composition was filled in the recess of the molded body. The wavelength-converting member composition was cured by heating at 150 °C for 3 hours to form a wavelength-converting member and form a resin encapsulation, thereby manufacturing a light-emitting device of the first mode.

[0135] Example 2

[0136] A wavelength-converting member composition containing 20 parts by mass of the phosphor 4 (β-sialon) having the composition shown in formula (3) with respect to 100 parts by mass of a silicone resin as a light-transmitting material was prepared, and a wavelength-converting member was formed using this wavelength-converting member composition. Otherwise, the same operations as in Example 1 were performed to manufacture a light-emitting device of the first mode.

[0137] Example 3

[0138] Prepare a composition for a wavelength conversion member that contains 10 parts by mass of a phosphor 5 (chlorosilicate) having the composition represented by formula (2) with respect to 100 parts by mass of a silicone resin as a light-transmitting material. Using this composition for a wavelength conversion member, form a wavelength conversion member, and perform the same operations as in Example 1 except for this, to manufacture a light-emitting device of the first mode.

[0139] Example 4

[0140] Using a light-emitting element that utilizes a nitride-based semiconductor with a peak wavelength of 494 nm, prepare a composition for a wavelength conversion member that contains 1 part by mass of a phosphor 6 (SCASN-1) having the composition represented by formula (4) with respect to 100 parts by mass of a silicone resin as a light-transmitting material. Using this composition for a wavelength conversion member, form a wavelength conversion member, and perform the same operations as in Example 1 except for this, to manufacture a light-emitting device of the first mode.

[0141] Example 5

[0142] Prepare a composition for a wavelength conversion member that contains 2 parts by mass of a phosphor 7 (SCASN-2) having the composition represented by formula (4) with respect to 100 parts by mass of a silicone resin as a light-transmitting material. Using this composition for a wavelength conversion member, form a wavelength conversion member, and perform the same operations as in Example 4 except for this, to manufacture a light-emitting device of the first mode.

[0143] Example 6

[0144] Prepare a composition for a wavelength conversion member that contains 2 parts by mass of a phosphor 8 (CASN-1) having the composition represented by formula (4) with respect to 100 parts by mass of a silicone resin as a light-transmitting material. Using this composition for a wavelength conversion member, form a wavelength conversion member, and perform the same operations as in Example 4 except for this, to manufacture a light-emitting device of the first mode.

[0145] Comparative Example 1

[0146] Prepare a light-emitting element that uses a nitride-based semiconductor with a peak wavelength of 449 nm. Using this light-emitting element, use a silicone resin as a light-transmitting material, and use a sealing member that does not contain a phosphor to replace the wavelength conversion member. Perform the same operations as in Example 1 except for this, to manufacture a light-emitting device of the first mode.

[0147] Comparative Example 2

[0148] Use a silicone resin as a light-transmitting material, and use a sealing member that does not contain a phosphor to replace the wavelength conversion member. Perform the same operations as in Example 1 except for this, to manufacture a light-emitting device of the first mode.

[0149] Comparative Example 3

[0150] An illuminating element using a nitride semiconductor having a main wavelength of 494 nm is prepared. Using this illuminating element, silicone resin is used as a light-transmitting material, and a sealing member not containing a phosphor is used instead of a wavelength conversion member. Otherwise, the same operations as in Example 1 are performed to manufacture a first-mode illuminating device.

[0151] Comparative Example 4

[0152] An illuminating element using a nitride semiconductor having a main wavelength of 449 nm is prepared. Using this illuminating element, a wavelength conversion member composition containing 45 parts by mass of phosphor 1 (BSiON) as a nitride phosphor with respect to 100 parts by mass of silicone resin as a light-transmitting material is prepared. Using this wavelength conversion member composition, a wavelength conversion member is formed. Otherwise, the same operations as in Example 1 are performed to manufacture a first-mode illuminating device.

[0153] Comparative Example 5

[0154] An illuminating element using a nitride semiconductor having a main wavelength of 449 nm is prepared. Using this illuminating element, a wavelength conversion member composition containing 80 parts by mass of phosphor 2 (SAE) as an aluminate phosphor with respect to 100 parts by mass of silicone resin as a light-transmitting material is prepared. Using this wavelength conversion member composition, a wavelength conversion member is formed. Otherwise, the same operations as in Example 1 are performed to manufacture a first-mode illuminating device.

[0155] Evaluation of Illuminating Element

[0156] Chromaticity coordinates (x E , y E ) and radiant flux

[0157] For each illuminating element used in the examples and comparative examples, using an optical measurement system combining a spectrophotometer (PMA-11, Hamamatsu Photonics K.K.) and an integrating sphere, the chromaticity coordinates (x E , y E ) in the chromaticity coordinate system of the CIE1931 chromaticity diagram and the radiant flux Fa are obtained.

[0158] Main Wavelength of Illuminating Element

[0159] Regarding the main wavelength of each illuminating element used in the examples and comparative examples, the chromaticity coordinates of white light (x = 0.3333, y = 0.3333) in the CIE1931 chromaticity diagram and the chromaticity coordinates (x E , y E ) of the emission color of each illuminating element are connected by a straight line, and the wavelength of the intersection point of the extension line and the spectral locus is obtained as the main wavelength. The results are shown in Table 2.

[0160] Evaluation of the light-emitting device

[0161] The chromaticity coordinates (x D , y D ), luminous flux, and radiant flux Fb

[0162] For each light-emitting device used in the examples and comparative examples, using an optical measurement system that combines a spectrophotometer (PMA-11, Hamamatsu Photonics Corporation) and an integrating sphere, the chromaticity coordinates (x D , y D ) in the chromaticity coordinate system of the CIE1931 chromaticity diagram, luminous flux, and radiant flux (total spectral radiant flux) were obtained. The chromaticity coordinates (x D , y D ) of each light-emitting device are shown in Table 2. The radiant flux Fb of each light-emitting device is shown in Table 3.

[0163] Dominant wavelength of the light-emitting device

[0164] For the dominant wavelength of each light-emitting device used in the examples and comparative examples, the chromaticity coordinates of white light (x = 0.3333, y = 0.3333) in the CIE1931 chromaticity diagram and the chromaticity coordinates (x D , y D ) of the emission color of each light-emitting device were connected by a straight line, and the wavelength of the intersection point of the extension line and the spectral locus was obtained as the dominant wavelength. The results are shown in Table 2.

[0165] Relative luminous flux of the light-emitting device

[0166] Taking the luminous flux of Comparative Example 1 as 100%, the relative values of the luminous fluxes of the light-emitting devices of Examples 1 to 6 and Comparative Examples 2 to 5 were obtained as the relative luminous fluxes. The results are shown in Table 2.

[0167] S / P ratio

[0168] For each light-emitting device of the examples and comparative examples, the ratio of the luminous flux in scotopic vision to the luminous flux in photopic vision, i.e., the S / P ratio, was calculated based on the above calculation formula (i). The S / P ratios are shown in Table 2.

[0169] Measurement of the emission spectrum of the light-emitting device

[0170] For each light-emitting device of the examples and comparative examples, using an optical measurement system that combines a spectrophotometer (PMA-11, Hamamatsu Photonics Corporation) and an integrating sphere, the emission spectrum at room temperature (25 °C ± 5 °C) was measured. For each light-emitting device, taking the maximum emission intensity in the emission spectrum of each light-emitting device as 1, the relative emission spectrum was obtained. At Figure 7The relative emission spectra of the light-emitting devices of Examples 1 to 3 are shown. In Figure 8 The relative emission spectra of the light-emitting devices of Examples 4 to 6 are shown. In Figure 9 The relative emission spectra of the light-emitting devices of Comparative Examples 1 to 5 are shown.

[0171] Ratio Ib / Ia of the integrated value of the emission intensity

[0172] In the relative emission spectra of the light-emitting devices of the examples and comparative examples, the ratio Ib / Ia of the integrated value Ib in the wavelength range of 380 nm or more and 531 nm or less to the integrated value Ia in the wavelength range of 380 nm or more and 780 nm or less was determined. The results are shown in Table 3.

[0173] Emission peak wavelength and emission intensity a of the light-emitting element in the emission spectrum of the light-emitting device

[0174] In the emission spectra of the light-emitting devices of the examples and comparative examples, the emission peak wavelength on the shorter wavelength side than the peak wavelength of the phosphor was determined as the emission peak wavelength of the light-emitting element in the emission spectrum of the light-emitting device, and the emission intensity at this emission peak wavelength was defined as the emission intensity a of the emission peak wavelength of the light-emitting element in the emission spectrum of the light-emitting device. The results are shown in Table 3.

[0175] Emission intensity b of the emission peak wavelength of the phosphor in the emission spectrum of the light-emitting device

[0176] In the emission spectra of the light-emitting devices of the examples and comparative examples, the emission intensity at the emission peak wavelength of each phosphor used in the light-emitting device was determined as the emission intensity b of the emission peak wavelength of the phosphor in the light-emitting device. The results are shown in Table 3.

[0177] Ratio a / b of the emission intensity

[0178] The ratio a / b of the emission intensity a of the emission peak wavelength of the light-emitting element in the emission spectrum of the light-emitting device to the emission intensity b of the emission peak wavelength of the phosphor in the emission spectrum of the light-emitting device was determined. The results are shown in Table 3.

[0179] Ratio Fb / Fa of the radiant flux

[0180] The ratio Fb / Fa of the radiant flux Fb of the light-emitting device to the radiant flux Fa of the light-emitting element was determined. The results are shown in Table 3.

[0181]

Table 2

[0182]

[0183]

Table 3

[0184]

[0185] The relative luminous flux of the light-emitting devices of Examples 1 to 6 is as high as over 450%, and the S / P ratio is 6.5 or less. In addition, for the light-emitting devices of Examples 1 to 6, the ratio Ib / Ia of the integral value Ib in the wavelength range of 380 nm or more and 531 nm or less to the integral value Ia in the wavelength range of 380 nm or more and 780 nm or less in the emission spectrum of the light-emitting device is in the range of 0.6 or more and 0.95 or less. It is considered that this is because by combining a phosphor having an emission peak wavelength of 507 nm or more, which is the peak wavelength of the spectral scotopic luminous efficiency, and a light-emitting element having a dominant wavelength in the range of 430 nm or more and 500 nm or less, the integral value range of the emission spectrum of the light-emitting device that overlaps with the integral value range of the photopic standard spectral luminous efficiency V(λ) increases.

[0186] In the light-emitting devices of Examples 1 to 6, the ratio Fb / Fa of the radiant flux Fb of the light-emitting device to the radiant flux Fa of the light-emitting element is as large as 0.75 or more, and the light emitted from the light-emitting element is efficiently wavelength-converted by the phosphor contained in the wavelength-converting member.

[0187] Furthermore, in the emission spectrum of the light-emitting devices of Examples 1 to 6, the ratio a / b of the emission intensity a at the emission peak wavelength of the light-emitting element to the emission intensity b at the emission peak wavelength of the phosphor is as large as 3.0 or more, the light emitted from the light-emitting element is stronger than the light wavelength-converted by the phosphor, and the desired light having a dominant wavelength in the wavelength range of blue to green including cyan is emitted from the light-emitting device.

[0188] In the light-emitting devices of Examples 1 to 6, according to the result of the ratio a / b of the emission intensity in the emission spectrum of the light-emitting device, the desired light having a dominant wavelength in the wavelength range of blue to green including cyan is emitted from the light-emitting device, and according to the results of the relative luminous flux and the ratio Fb / Fa of the radiant flux, excellent visibility that appears bright both in scotopic vision and photopic vision is maintained.

[0189] In addition, in the light-emitting devices of Examples 1 to 6, according to the results of the S / P ratio and the ratio Ib / Ia of the integral value, it can be confirmed that light is emitted with reduced glare that is perceived by humans both in scotopic vision and photopic vision.

[0190] As Figure 7 and Figure 8 shown, the integral value range of the emission spectrum of the light-emitting devices of Examples 1 to 6 increases in the range where the emission spectrum overlaps with the integral value range of the photopic standard spectral luminous efficiency V(λ).

[0191] The S / P ratios of the light-emitting devices of Comparative Examples 1 to 3 increase and exceed 6.5.

[0192] In addition, since the light-emitting devices of Comparative Examples 1 to 3 do not contain a phosphor, the ratio Ib / Ia of the integral value Ib in the wavelength range of 380 nm or more and 531 nm or less to the integral value Ia in the wavelength range of 380 nm or more and 780 nm or less in the emission spectrum of the light-emitting device increases and exceeds 0.95. It is considered that this is because, since there is no phosphor, the integral value range of the emission spectrum of the light-emitting device overlapping with the integral value range of the photopic standard spectral luminous efficiency V(λ) is small. The S / P ratios of the light-emitting devices of Comparative Examples 1 to 3 increase and exceed 6.5. Therefore, there is a difference in the brightness perceived by the human eye between bright and dark places. In the dark, it is possible to feel dazzled by the light emitted from the light-emitting device having a dominant wavelength in the wavelength range of blue to green including cyan.

[0193] The S / P ratio of the light-emitting device of Comparative Example 4 is 6.5. However, the ratio Ib / Ia of the integral value Ib in the wavelength range of 380 nm or more and 531 nm or less to the integral value Ia in the wavelength range of 380 nm or more and 780 nm or less in the emission spectrum of the light-emitting device increases and exceeds 0.95. It is considered that this is because the phosphor contained in the light-emitting device has an emission peak wavelength smaller than the peak wavelength of the scotopic spectral luminous efficiency, that is, 507 nm. Therefore, the integral value range of the emission spectrum of the light-emitting device overlapping with the integral value range of the photopic standard spectral luminous efficiency V(λ) is small. For the light-emitting device of Comparative Example 4, it is possible to feel dazzled by the light emitted from the light-emitting device having a dominant wavelength in the wavelength range of blue to green including cyan in the dark. In addition, in the light-emitting device of Comparative Example 4, the ratio Fb / Fa of the radiant flux Fb of the light-emitting device to the radiant flux Fa of the light-emitting element is 0.75 or less, and the wavelength conversion efficiency of the phosphor excited by the light emitted from the light-emitting element is low, and excellent visibility cannot be maintained.

[0194] The S / P ratio of the light-emitting device of Comparative Example 5 is 6.5 or less, and the ratio Ib / Ia of the integral value Ib in the wavelength range of 380 nm or more and 531 nm or less to the integral value Ia in the wavelength range of 380 nm or more and 780 nm or less in the emission spectrum of the light-emitting device is 0.95 or less. However, the ratio Fb / Fa of the radiant flux Fb of the light-emitting device to the radiant flux Fa of the light-emitting element is as low as 0.74, and the wavelength conversion efficiency of the phosphor is poor. In addition, the ratio a / b of the emission intensity in the emission spectrum of the light-emitting device of Comparative Example 5 is as small as 0.29, and the light emitted from the light-emitting element is weaker than the light wavelength-converted by the phosphor, and excellent visibility cannot be maintained.

[0195] As Figure 9 shown, in the emission spectra of the light-emitting devices of Comparative Examples 1 to 3, the emission spectrum of the light emitted from the light-emitting element could be confirmed, but the range overlapping with the integral value range of the photopic standard spectral luminous efficiency V(λ) was small, and there was a difference in the brightness perceived by the human eye in bright and dark places. In the dark, there was a possibility of being dazzled by the light emitted from the light-emitting device having a dominant wavelength in the wavelength range of blue to green including cyan. In addition, as Figure 9 shown, in the emission spectra of the light-emitting devices of Comparative Examples 4 and 5, the ratio a / b of the emission intensity a of the emission peak wavelength of the light-emitting element to the emission intensity b of the emission peak wavelength of the phosphor was small, and it was impossible to maintain excellent visibility that appeared bright both in scotopic and photopic vision.

[0196] As Figure 10 shown, on the CIE1931 chromaticity diagram, the chromaticity coordinates (x D [[ID= y D ) of the emission color of the light-emitting devices of Examples 1 to 6 all fell within the target hue range (region A), and an emission color of the target hue was obtained.

[0197] As Figure 11 shown, on the CIE1931 chromaticity diagram, the chromaticity coordinates (x D ,y D ) of the emission color of the light-emitting devices of Comparative Examples 3 to 5 fell within the target hue range (region A), and an emission color of the target hue was obtained. However, the chromaticity coordinates (x D ,y D ) of the emission color of the light-emitting devices of Comparative Examples 1 and 2 deviated from the target hue range (region A), and an emission color of the target hue was not obtained.

[0198] Example 7

[0199] Manufacture a light-emitting device of the second method.

[0200] In the process of arranging the light-emitting element, a ceramic substrate made of aluminum nitride is used as the substrate. As the light-emitting element, a light-emitting element in which a nitride semiconductor layer having a dominant wavelength of 488 nm is laminated is used. The size of the light-emitting element is a substantially square planar shape of about 1.0 mm square, and the thickness is about 0.11 mm. The light-emitting element is arranged such that the light-emitting surface faces the substrate side, and flip-chip mounting is performed using bumps made of a conductive member made of Au. In addition, using bumps made of a conductive member made of Au, the semiconductor element and the light-emitting element are flip-chip mounted with a space therebetween.

[0201] In the process of forming a wavelength conversion body including a wavelength conversion member, a wavelength conversion member composition was prepared as follows: 46 parts by mass of a phosphor 3(LAG)4 having the composition represented by the formula (1) was included with respect to 100 parts by mass of a silicone resin as a light-transmitting material, 5 parts by mass of alumina as a filler was included, and 30 parts by mass of spherical silica having an average particle diameter of 11 μm (value in the product specification) was included to stabilize the shape. As the light-transmitting body, a light-transmitting body made of borosilicate glass was prepared, which had a planar shape that was approximately 0.15 mm larger than the planar shape of the light-emitting element in both the longitudinal and transverse directions, was a substantially square with a planar shape of approximately 1.15 mm square, and had a thickness of approximately 0.10 mm. The wavelength conversion member composition was printed on one substantially square surface of the light-transmitting body by a printing method, and heated at 150°C for 3 hours to cure the wavelength conversion member composition, thereby forming a layered wavelength conversion member with a thickness of approximately 80 μm, and forming a wavelength conversion body in which the layered wavelength conversion member and the light-transmitting body were integrated.

[0202] In the bonding process of the light-emitting element and the wavelength conversion member, one substantially square surface of the wavelength conversion member with a planar shape of approximately 1.15 mm square was bonded to one substantially square surface of the light-emitting element with a planar shape of approximately 1.0 mm square using an adhesive containing a silicone resin, and a bonding layer was formed between the light-emitting element and the wavelength conversion member. Regarding the bonding surface of the wavelength conversion member with the light-emitting element, the bonding surface of the wavelength conversion member was approximately 0.15 mm larger than the bonding surface of the light-emitting element in both the longitudinal and transverse directions. Therefore, the adhesive exposed from the bonding surface of the light-emitting element adhered to the side surface of the light-emitting element, forming an exposed portion of the bonding layer having a substantially triangular cross-sectional shape. The exposed portion of the bonding layer adhering to the side surface of the light-emitting element had a triangular shape with the thickness of the layer decreasing toward the lower side of the light-emitting element and had an inclination extending toward the wavelength conversion member side upward.

[0203] In the process of forming the coating member, a coating member composition containing a dimethyl silicone resin and titanium oxide particles having an average particle diameter (value in the product specification) of 0.28 μm and including 30 parts by mass of titanium oxide particles with respect to 100 parts by mass of the dimethyl silicone resin was prepared. The side surfaces of the wavelength conversion body including the light-emitting element, the wavelength conversion member, and the light-transmitting body disposed on the substrate were covered with the coating member composition, and the coating member composition was filled in such a manner that the semiconductor element was completely buried in the coating member composition, and the coating member composition was cured to form a coating member, thereby forming a resin package and manufacturing a light-emitting device of the second mode.

[0204] Example 8

[0205] Prepare a wavelength conversion member composition containing 60 parts by mass of phosphor 4 (β-sialon) having the composition represented by the formula (3) relative to 100 parts by mass of a silicone resin as a light-transmitting material, and containing 5 parts by mass of alumina as a filler. Using this wavelength conversion member composition, perform the same operations as in Example 7 except for this, to manufacture a light-emitting device of the second mode.

[0206] Example 9

[0207] Prepare a wavelength conversion member composition containing 23 parts by mass of phosphor 5 (chlorosilicate) having the composition represented by the formula (2) relative to 100 parts by mass of a silicone resin as a light-transmitting material, containing 5 parts by mass of alumina as a filler, and 30 parts by mass of spherical silica having an average particle diameter of 11 μm (value in the product manual) for stabilizing the shape. Using this wavelength conversion member composition, perform the same operations as in Example 7 except for this, to manufacture a light-emitting device of the second mode.

[0208] Example 10

[0209] Use a light-emitting element in which a nitride semiconductor layer having a peak wavelength of 495 nm is laminated as the light-emitting element, and perform the same operations as in Example 7 except for this, to manufacture a light-emitting device of the second mode.

[0210] Example 11

[0211] Use a light-emitting element in which a nitride semiconductor layer having a peak wavelength of 495 nm is laminated as the light-emitting element, and perform the same operations as in Example 8 except for this, to manufacture a light-emitting device of the second mode.

[0212] Example 12

[0213] Use a light-emitting element in which a nitride semiconductor layer having a peak wavelength of 495 nm is laminated as the light-emitting element, and perform the same operations as in Example 9 except for this, to manufacture a light-emitting device of the second mode.

[0214] Example 13

[0215] Use a light-emitting element in which a nitride semiconductor layer having a peak wavelength of 495 nm is laminated as the light-emitting element, and use a wavelength conversion member composition containing 4 parts by mass of phosphor 6 (SCASN-1) having the composition represented by the formula (4) relative to 100 parts by mass of a silicone resin as a light-transmitting material, containing 5 parts by mass of alumina as a filler, and 30 parts by mass of spherical silica having an average particle diameter of 11 μm (value in the product manual). Perform the same operations as in Example 7 except for this, to manufacture a light-emitting device of the second mode.

[0216] Comparative Example 6

[0217] Using a light-emitting element that utilizes a nitride-based semiconductor with a main wavelength of 449 nm, instead of the wavelength-converting member composition, a light-diffusing member composition containing 10 parts by mass of alumina as a filler with respect to 100 parts by mass of a silicone resin as a light-transmissive material was prepared. The light-diffusing member composition was coated on a light-transmissive body with a thickness of about 0.15 mm to form a layer-like light-diffusing member with a thickness of about 35 μm. The light-diffusing member was bonded to the light-emitting element, and in other respects, the operation was the same as in Example 7, and a second-type light-emitting device including a light-diffusing member instead of a wavelength-converting member was manufactured.

[0218] Comparative Example 7

[0219] Using a light-emitting element that utilizes a nitride-based semiconductor with a main wavelength of 488 nm, and in other respects, the operation was the same as in Comparative Example 6, and a second-type light-emitting device including a light-diffusing member instead of a wavelength-converting member was manufactured.

[0220] Comparative Example 8

[0221] Using a light-emitting element that utilizes a nitride-based semiconductor with a main wavelength of 492 nm, and in other respects, the operation was the same as in Comparative Example 6, and a second-type light-emitting device including a light-diffusing member instead of a wavelength-converting member was manufactured.

[0222] Comparative Example 9

[0223] Using a light-emitting element that utilizes a nitride-based semiconductor with a main wavelength of 495 nm, and in other respects, the operation was the same as in Comparative Example 6, and a second-type light-emitting device including a light-diffusing member instead of a wavelength-converting member was manufactured.

[0224] Comparative Example 10

[0225] Using a light-emitting element that utilizes a nitride-based semiconductor with a main wavelength of 449 nm, using a wavelength-converting member composition containing 150 parts by mass of phosphor 1 (BSiON) as an aluminate phosphor and 20 parts by mass of alumina as a filler with respect to 100 parts by mass of a silicone resin as a light-transmissive material, and in other respects, the operation was the same as in Example 7, and a second-type light-emitting device was manufactured.

[0226] Comparative Example 11

[0227] Using a light-emitting element that utilizes a nitride-based semiconductor with a main wavelength of 449 nm, using a wavelength-converting member composition containing 150 parts by mass of phosphor 2 (SAE) as an aluminate phosphor and 20 parts by mass of alumina as a filler with respect to 100 parts by mass of a silicone resin as a light-transmissive material, and in other respects, the operation was the same as in Example 7, and a second-type light-emitting device was manufactured.

[0228] Evaluation of Light-Emitting Elements

[0229] The chromaticity coordinates (x E , y E ), radiant flux, and peak wavelength of the light-emitting elements used in Examples 7 to 13 and Comparative Examples 6 to 11 were determined in the same manner as those of the light-emitting element used in Example 1.

[0230] Evaluation of Light-Emitting Devices

[0231] The light-emitting devices of Examples 7 to 13 and Comparative Examples 6 to 11 were operated in the same manner as in Example 1, and the chromaticity coordinates (x D , y D ), luminous flux, radiant flux Fb, peak wavelength, relative luminous flux, S / P ratio, emission spectrum, ratio of integrated values Ib / Ia, peak wavelength and luminous intensity a of the light-emitting element in the emission spectrum of the light-emitting device, peak wavelength and luminous intensity b of the phosphor in the emission spectrum of the light-emitting device, ratio of luminous intensities a / b, and ratio of radiant fluxes Fb / Fa were determined. Regarding the relative luminous flux, the luminous flux of Comparative Example 6 was set to 100%, and the relative values of the luminous fluxes of the light-emitting devices of Examples 7 to 13 and Comparative Examples 7 to 11 were determined. The results are shown in Tables 4 and 5. The relative emission spectra of the light-emitting devices of Examples 7 to 9 are shown in Figure 12 . The relative emission spectra of the light-emitting devices of Examples 10 to 13 are shown in Figure 13 . The relative emission spectra of the light-emitting devices of Comparative Examples 6 to 11 are shown in Figure 14 .

[0232]

Table 4

[0233]

[0234]

Table 5

[0235]

[0236] The relative luminous flux of the light-emitting devices of Examples 7 to 13 is as high as 500% or more, and the S / P ratio is 6.5 or less. In addition, for the light-emitting devices of Examples 7 to 13, the ratio Ib / Ia of the integral value Ib in the wavelength range of 380 nm or more and 531 nm or less to the integral value Ia in the wavelength range of 380 nm or more and 780 nm or less in the emission spectrum of the light-emitting device is in the range of 0.6 or more and 0.95 or less. It is considered that this is because by combining a phosphor having an emission peak wavelength of 507 nm or more, which is the peak wavelength of the spectral luminous efficiency in scotopic vision, with a light-emitting element having a dominant wavelength in the range of 430 nm or more and 500 nm or less, the integral value range of the emission spectrum of the light-emitting device that overlaps with the integral value range of the photopic standard spectral luminous efficiency V(λ) increases.

[0237] In the light-emitting devices of Examples 7 to 13, the ratio Fb / Fa of the radiant flux Fb of the light-emitting device to the radiant flux Fa of the light-emitting element is as large as 0.75 or more, and the light emitted from the light-emitting element becomes more efficient based on the wavelength conversion efficiency of the phosphor contained in the wavelength conversion member.

[0238] In addition, in the emission spectrum of the light-emitting devices of Examples 7 to 13, the ratio a / b of the emission intensity a at the emission peak wavelength of the light-emitting element to the emission intensity b at the emission peak wavelength of the phosphor is as large as 3.0 or more, and the light emitted from the light-emitting element is stronger than the light wavelength-converted by the phosphor, and the desired light having a dominant wavelength in the wavelength range of blue to green including blue-green is emitted from the light-emitting device.

[0239] In the light-emitting devices of Examples 7 to 13, according to the result of the ratio a / b of the emission intensity, the desired light having a dominant wavelength in the wavelength range of blue to green including blue-green is emitted from the light-emitting device, and according to the results of the relative luminous flux and the ratio Fb / Fa of the radiant flux, excellent visibility that appears bright both in scotopic vision and photopic vision is maintained.

[0240] In addition, in the light-emitting devices of Examples 7 to 13, it can be confirmed from the results of the S / P ratio and the ratio Ib / Ia of the integral value that light is emitted with reduced glare that is felt by humans both in scotopic vision and photopic vision.

[0241] As Figure 12 and 13 shown, the integral value range of the emission spectrum of the light-emitting devices of Examples 7 to 13 increases in the range where the emission spectrum overlaps with the integral value range of the photopic standard spectral luminous efficiency V(λ).

[0242] The S / P ratio of the light-emitting devices of Comparative Examples 6 to 9 becomes larger and exceeds 6.5.

[0243] In addition, since the light-emitting devices of Comparative Examples 6 to 9 use a light-diffusing member that does not contain a phosphor instead of a wavelength-converting member that contains a phosphor, the ratio Ib / Ia of the integral value Ib in the wavelength range of 380 nm or more and 531 nm or less to the integral value Ia in the wavelength range of 380 nm or more and 780 nm or less in the emission spectrum of the light-emitting device becomes larger and exceeds 0.95. It is considered that this is because, since there is no phosphor, the integral value range of the emission spectrum of the light-emitting device that overlaps with the integral value range of the photopic standard spectral luminous efficiency V(λ) is small. Since the S / P ratio of the light-emitting devices of Comparative Examples 6 to 9 becomes larger and exceeds 6.5, there is a difference in the brightness perceived by the human eye between the bright and dark places, and in the dark place, it is possible to be dazzled by the light emitted from the light-emitting device having a dominant wavelength in the wavelength range of blue to green including cyan.

[0244] The S / P ratio of the light-emitting device of Comparative Example 10 is 6.5 or less, but the ratio Ib / Ia of the integral value Ib in the wavelength range of 380 nm or more and 531 nm or less to the integral value Ia in the wavelength range of 380 nm or more and 780 nm or less in the emission spectrum of the light-emitting device becomes larger and exceeds 0.95. It is considered that this is because, since the phosphor contained in the light-emitting device has an emission peak wavelength smaller than the peak wavelength of the spectral standard luminous efficiency under scotopic vision, which is 507 nm, the integral value range of the emission spectrum of the light-emitting device that overlaps with the integral value range of the photopic standard spectral luminous efficiency V(λ) is small. For the light-emitting device of Comparative Example 10, it is possible to be dazzled by the light emitted from the light-emitting device having a dominant wavelength in the wavelength range of blue to green including cyan in the dark place. In addition, in the light-emitting device of Comparative Example 10, the ratio Fb / Fa of the radiant flux Fb of the light-emitting device to the radiant flux Fa of the light-emitting element is as small as 0.31, and the ratio a / b of the luminous intensity in the emission spectrum of the light-emitting device is as small as 0.1 and less than 1.0, and the wavelength conversion efficiency of the phosphor excited by the light emitted from the light-emitting element is low. In order to reduce the S / P ratio and ensure excellent visibility, the light-emitting device of Comparative Example 10 requires a larger amount of phosphor than the example.

[0245] The S / P ratio of the light-emitting device of Comparative Example 11 was 6.5 or less, and the ratio Ib / Ia of the integrated value Ib in the wavelength range of 380 nm or more and 531 nm or less to the integrated value Ia in the wavelength range of 380 nm or more and 780 nm or less in the emission spectrum of the light-emitting device was 0.95 or less. However, the ratio Fb / Fa of the radiant flux Fb of the light-emitting device to the radiant flux Fa of the light-emitting element was as low as 0.69, and the wavelength conversion efficiency of the phosphor was poor. In addition, the ratio a / b of the emission intensity in the emission spectrum of the light-emitting device of Comparative Example 11 was 0.5 and less than 1.0, and the wavelength conversion efficiency of the phosphor excited by the light emitted from the light-emitting element was low. The light-emitting device of Comparative Example 11 required a larger amount of phosphor than the Example in order to reduce the S / P ratio and thereby ensure excellent visibility.

[0246] As Figure 14 shown, in the emission spectra of the light-emitting devices of Comparative Examples 6 to 9, the emission spectrum of the light emitted from the light-emitting element could be confirmed, but the overlapping range with the integrated value range of the photopic standard spectral luminous efficiency V(λ) was small, and there was a difference in the brightness perceived by the human eye in bright and dark places. There was a possibility of glare from the light emitted from the light-emitting device having a dominant wavelength in the wavelength range of blue to green including cyan in the dark. In addition, as Figure 14 shown, in the emission spectra of the light-emitting devices of Comparative Examples 10 and 11, the ratio a / b of the emission intensity a at the emission peak wavelength of the light-emitting element to the emission intensity b at the emission peak wavelength of the phosphor was small.

[0247] As Figure 15 shown, on the CIE1931 chromaticity diagram, the chromaticity coordinates (x D , y D ) of the emission color of the light-emitting devices of Examples 7 to 13 all fell within the target hue range (Region A), and an emission color of the target hue was obtained.

[0248] As Figure 16 shown, on the CIE1931 chromaticity diagram, the chromaticity coordinates (x D , y D ) of the emission color of the light-emitting devices of Comparative Examples 8 to 10 fell within the target hue range (Region A), and an emission color of the target hue was obtained. However, the chromaticity coordinates (x D , y D ) of the emission color of the light-emitting devices of Comparative Examples 6, 7, and 11 deviated from the target hue range (Region A), and an emission color of the target hue was not obtained.

[0249] Industrial Applicability

[0250] The light-emitting device according to one embodiment of the present invention can be used as a light-emitting device for general illumination, a light-emitting device for vehicles, a display device, a lighting fixture, a display, etc.

[0251] Description of Reference Numerals

[0252] 11, 12: Light-emitting elements, 13: Semiconductor element, 21: Phosphor, 31, 32: Wavelength conversion members, 33: Translucent body, 34: Wavelength conversion body, 41: Formed body, 42: Resin portion, 51: First lead wire, 52: Second lead wire, 61, 62: Conductive members, 72: Substrate, 82: Adhesive layer, 92: Coating member, 100, 200: Light-emitting devices.

Claims

1. A light-emitting device, comprising: a light-emitting element having a main wavelength in the range of more than 430 nm and less than 500 nm; and a phosphor that is excited by the light of the light-emitting element and has an emission peak wavelength in the range of more than 507 nm and less than 660 nm, the light-emitting device emits light having a main wavelength in the range of more than 490 nm and less than 500 nm, the ratio of the luminous flux under scotopic vision to the luminous flux under photopic vision, i.e., the S / P ratio, is 6.5 or less, the luminous intensity at the emission peak wavelength of the light-emitting element is higher than the luminous intensity at the emission peak wavelength of the phosphor, the light-emitting device emits light whose chromaticity coordinates (x, y) are in the following region in the xy chromaticity coordinate system of the CIE XYZ color space: the region is defined by a first point (x = 0.0082, y = 0.5384), a second point (x = 0.0454, y = 0.2950), a third point (x = 0.2000, y = 0.3200), a fourth point (x = 0.2000, y = 0.4000), 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.

2. The light-emitting device according to claim 1, wherein The S / P ratio is 6.0 or less.

3. The light-emitting device according to claim 1 or 2, wherein, The S / P ratio is 2.0 or more.

4. The light-emitting device according to claim 1 or 2, wherein, In the emission spectrum of the light-emitting device, the ratio Ib / Ia of the integral value Ib in the wavelength range of more than 380 nm and less than 531 nm to the integral value of the emission spectrum in the wavelength range of more than 380 nm and less than 780 nm is in the range of 0.6 or more and 0.95 or less.

5. The light-emitting device according to claim 1 or 2, wherein, In the emission spectrum of the light-emitting device, the ratio a / b of the luminous intensity a at the emission peak wavelength of the light-emitting element to the luminous intensity b at the emission peak wavelength of the phosphor is 3.0 or more.

6. The light-emitting device according to claim 1 or 2, wherein, The ratio Fb / Fa of the radiant flux Fb of the light-emitting device to the radiant flux Fa of the light-emitting element is 0.75 or more.

7. The light-emitting device according to claim 1 or 2, comprising a wavelength conversion member including the phosphor and a light-transmitting material, and the wavelength conversion member contains the phosphor in the range of 0.5 parts by mass or more and 65 parts by mass or less with respect to 100 parts by mass of the light-transmitting material.

8. The light-emitting device according to claim 1 or 2, wherein, The half-value width of the phosphor is 45 nm or more and 120 nm or less.

9. The light-emitting device according to claim 1 or 2, wherein, The phosphor includes at least one phosphor selected from the following phosphors: a rare earth aluminate phosphor having a composition containing Ce, Al, at least one element Ln selected from Y, La, Lu, Gd, and Tb, and optionally at least one element selected from Ga and Sc; a β-sialon phosphor having a composition containing Si, Al, O, N, and Eu; a halosilicate phosphor having a composition containing Ca, Eu, Mg, Si, O, and at least one halogen element selected from F, Cl, and Br; and A nitride phosphor having a composition containing Ca, Eu, Si, Al, N and Sr optionally contained therein.

10. The light-emitting device according to claim 1 or 2, wherein, The phosphor contains at least one phosphor selected from a rare earth aluminate phosphor having a composition represented by the following formula (1), a halosilicate phosphor having a composition represented by the following formula (2), a β-sialon phosphor having a composition represented by the following formula (3), and a nitride phosphor having a composition represented by the following formula (4). (Y, Lu, Gd)3(Al, Ga)5O 12 : Ce (1) (Ca, Sr, Ba)8MgSi4O 16 (F, Cl, Br)2:Eu(2) Si 6-z Al z O z N 8-z : Eu, 0 ≤ z ≤ 4.2 (3) (Sr, Ca)AlSiN3:Eu (4).

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