Light-emitting device

Abstract

To provide a light-emitting device which makes both scotopic vision and photopic vision bright and is capable of inducing an image in a specific state.SOLUTION: The present invention relates to a light-emitting device comprising: a light-emitting element having a main wavelength in a range from 400 nm or more to 500 nm or less; and a wavelength converting member disposed at an emission side of light of the light-emitting element and containing a rare earth aluminate phosphor having a composition expressed by the formula (I) (Lu1-p-nLnpCen)3(Al1-mGam)5kO12. The light-emitting device emits light having a main wavelength in a range from 475 nm or more to 500 nm or less and an S / P ratio derived from the formula (1) which is a ratio of a light flux in scotopic vision with respect to a light flux in photopic vision is 6.5 or less. (In the formula (I), Ln is at least one rare earth element selected from among Y, La, Gd and Tb and k, m, n and p satisfy 0.95≤k≤1.05, 0.05≤m≤0.70, 0.002≤n≤0.050 and 0≤p≤0.30.)SELECTED DRAWING: Figure 6B

Description

[Technical field]

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

[0002] Known light-emitting devices using light-emitting elements such as light-emitting diodes (LEDs) include light-emitting devices that emit mixed color light using a light-emitting element that emits blue light and a phosphor that is excited by light from the light-emitting element and emits light. Such light-emitting devices are used in a wide range of fields, such as general lighting, vehicle lighting, displays, and liquid crystal backlights.

[0003] In recent years, light-emitting devices that take into consideration the effects on humans have been attracting attention. For example, it is known that when humans perceive light, the luminosity of the human eye changes between dark and bright places. In bright environments, known as photopic vision, color perception is possible through the action of cone cells, which are the photoreceptor cells (photoreceptor cells) of the human eye. In dark environments, known as scotopic vision, many colors cannot be perceived because cone cells do not function, but luminosity is improved through the action of rod cells.

[0004] It is known that the peak wavelength of visual sensitivity due to cone cells, which are active in bright places, is 555 nm, while the peak wavelength of visual sensitivity due to rod cells, which are active in dark places, is 507 nm, and that the peak of visual sensitivity differs between dark and bright places. This phenomenon is known as the Purkinje phenomenon, in which colors on the longer wavelength side appear more vivid in bright places and colors on the shorter wavelength side appear more vivid in dark places.

[0005] For example, Patent Document 1 proposes a lighting device utilizing the Purkinje phenomenon, which is a road light that emits white light and provides high visibility to drivers on the sidewalk side and high visibility to pedestrians in a mesopic vision environment with intermediate brightness between dark and bright places, and makes it difficult to perceive color spots on the roadway side and the sidewalk side. Patent Document 1 states that the higher the S / P ratio, which is the ratio of scotopic vision to photopic vision, the higher the visibility of the light in a mesopic vision environment. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2017-220312 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, if the S / P ratio is too high, the human eye may perceive the light as dark in photopic vision and bright in scotopic vision. In addition, there are cases where a light-emitting device is required to emit a light color that can evoke a specific state, such as charging a mobile device, and it is necessary to consider the effect of the light emitted by such a light-emitting device on humans. One aspect of the present invention aims to provide a light-emitting device that is bright in both scotopic and photopic vision, emits an emission color that can evoke an image of a specific state or the like, and takes into consideration its effects on humans. [Means for solving the problem]

[0008] One aspect of the present invention is a light emitting device including: a light emitting element having a dominant wavelength in the range of 400 nm to 500 nm; and a wavelength conversion member that is disposed on a light emission side of the light emitting element and contains a rare earth aluminate phosphor having a composition represented by the following formula (I): (Lu 1-p-n Ln p Ce n )3(Al 1-m Ga m ) 5k O 12(I) (In formula (I), Ln is at least one rare earth element selected from the group consisting of Y, La, Gd, and Tb, and k, m, n, and p satisfy 0.95≦k≦1.05, 0.05≦m≦0.70, 0.002≦n≦0.050, and 0≦p≦0.30, respectively.) Emits light having a dominant wavelength within the range of 475 nm to 500 nm, The light emitting device has an S / P ratio, which is the ratio of luminous flux in scotopic vision to luminous flux in photopic vision, calculated from the following formula (1), of 6.5 or less.

number

[0009] Another aspect of the present invention is a light emitting device including a light emitting element having a dominant wavelength in the range of 400 nm to 500 nm, and a wavelength conversion member disposed on a light emission side of the light emitting element and including a rare earth aluminate phosphor having a composition represented by the following formula (I): (Lu 1-p-n Ln p Ce n )3(Al 1-m Ga m ) 5k O 12 (I) (In formula (I), Ln is at least one rare earth element selected from the group consisting of Y, La, Gd, and Tb, and k, m, n, and p satisfy 0.95≦k≦1.05, 0.05≦m≦0.70, 0.002≦n≦0.050, and 0≦p≦0.30, respectively.) Emits light having a dominant wavelength within the range of 475 nm to 500 nm, The light-emitting device has a melanopic ratio, calculated from the following formula (2), of 3.4 or less.

number

[0010] According to an aspect of the present invention, it is possible to provide a light-emitting device that is bright in both scotopic and photopic vision, emits a light color that evokes an image of a specific state, such as when charging, and takes into consideration its impact on humans. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing the standard spectral luminous efficiency for photopic vision V(λ) and the standard spectral luminous efficiency for scotopic vision V'(λ). [Diagram 2] FIG. 2 shows the sensitivity curve (Circadian) of intrinsically photosensitive retinal ganglion cells, which are photoreceptors in the mammalian retina, and the luminosity curve (Visual) in human photopic vision. [Diagram 3] FIG. 3 is a diagram showing an area A1 in the xy chromaticity coordinate system of the CIE 1931 chromaticity diagram. [Figure 4] FIG. 4 is a diagram showing an area A2 in the xy chromaticity coordinate system of the CIE 1931 chromaticity diagram. [Diagram 5] FIG. 5 is a diagram showing an area A3 in the xy chromaticity coordinate system of the CIE 1931 chromaticity diagram. [Figure 6A] FIG. 6A is a schematic plan view of a light emitting device according to a first configuration example. [Figure 6B] FIG. 6B is a schematic cross-sectional view of the light emitting device of the first configuration example. [Figure 7] FIG. 7 is a schematic cross-sectional view of a light emitting device according to the second configuration example. [Figure 8] FIG. 8 is a schematic cross-sectional view of a light emitting device according to the third configuration example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The light emitting device according to the present invention will be described below based on the embodiments. However, the embodiments shown below are merely examples for embodying the technical idea of ​​the present invention, and the present invention is not limited to the light emitting device described below. The relationship between the color name and the chromaticity coordinates, and the relationship between the wavelength range of light and the color name of monochromatic light are in accordance with JIS Z8110. Furthermore, when there are multiple substances corresponding to each component in the composition, the content of each component in the composition means the total amount of multiple substances present in the composition, unless otherwise specified.

[0013] Light-emitting device One embodiment of the light emitting device is a light emitting device comprising a light emitting element having a dominant wavelength in the range of 400 nm or more and 500 nm or less, and a wavelength conversion member that is arranged on the light emission side of the light emitting element and contains a rare earth aluminate phosphor having a composition represented by formula (I) described below, wherein the light emitting device emits light having a dominant wavelength in the range of 475 nm or more and 500 nm or less, and has an S / P ratio of 6.5 or less, which is derived from formula (1) described below, which is the ratio of the luminous flux in photopic vision to the luminous flux in scotopic vision.

[0014] The dominant wavelength of a light-emitting element is the ratio between the chromaticity coordinates of white light (x=0.3333, y=0.3333) in the CIE1931 chromaticity diagram defined by the CIE (International Commission on Illumination: Commission international de l'eclairage) and the chromaticity coordinates of the light-emitting color of the light-emitting element (x E , y E) with a straight line and the extended line intersects with the spectral locus. The spectral locus is a curve obtained by connecting the chromaticity points of monochromatic (pure) light on a chromaticity diagram. The dominant wavelength of a light-emitting device is the wavelength at the point where the extended line of a line connecting the chromaticity coordinates (x=0.3333, y=0.3333) of white light on the CIE1931 chromaticity diagram with the chromaticity coordinates (x, y) of the emitted color of the light-emitting device intersects with the spectral locus.

[0015] The light emitting device includes a light emitting element having a dominant wavelength in the wavelength range from blue to blue-green and a phosphor having an emission peak wavelength in the wavelength range of green, and emits light having a dominant wavelength in the wavelength range from blue to green including blue-green. It is known that the higher the S / P ratio, which is the ratio of the luminous flux in scotopic vision to the luminous flux in photopic vision, the higher the human visibility. FIG. 1 is a diagram showing the standard spectral luminous efficiency V(λ) for photopic vision and the standard spectral luminous efficiency V'(λ) for scotopic vision. The standard spectral luminous efficiency V(λ) for photopic vision and the standard spectral luminous efficiency V'(λ) for scotopic vision are specified by the CIE. As shown in FIG. 1, the peak wavelength in the standard spectral luminous efficiency V(λ) for photopic vision is 555 nm, and the peak wavelength in the standard spectral luminous efficiency V'(λ) for scotopic vision is 507 nm, and the peak of luminosity is different between dark and bright places. It is known that the peak wavelength of the luminosity of the human eye is different in a bright place and in a dark place, and that the human eye sees colors on the long wavelength side vividly in a bright place and colors on the short wavelength side vividly in a dark place due to the Purkinje phenomenon. When the S / P ratio of a light emitting device that emits light having a dominant wavelength in the purple to green wavelength range is increased to improve visibility, the colors on the short wavelength side may become too vivid and appear too bright when viewed in a dark place. The light emitting device according to the embodiment of the present invention has an S / P ratio of 6.5 or less even when emitting light having a dominant wavelength in the blue to green wavelength range including blue-green, and is considered to be able to reduce the difference between the luminous flux in a dark place and the luminous flux in a bright place, to appear bright in both scotopic and photopic vision, and to maintain excellent visibility.

[0016] The S / P ratio, which is the ratio of luminous flux in a dark place to luminous flux in a bright place, can be derived from the following formula (1).

[0017]

number

[0018] In formula (1), the constant K is 6831 (lm / W), the constant K' is 1700 (lm / W), and within the wavelength λ range of 360 nm or more and 830 nm or less, V(λ) is the standard spectral luminous efficiency for human photopic vision, V'(λ) is the standard spectral luminous efficiency for human scotopic vision, and Φ e (λ) is the spectral total radiant flux of the light emitted from the light emitting device.

[0019] The S / P ratio, which is the ratio of the luminous flux in scotopic vision to the luminous flux in photopic vision of the light emitted from the light emitting device, is 6.5 or less, preferably 6.0 or less, preferably 2.0 or more, and more preferably 3.0 or more. By reducing the S / P ratio of the light emitted from the light emitting device to 6.5 or less and reducing the difference between the luminous flux in scotopic vision and the luminous flux in photopic vision, it is considered that even a light emitting device that emits light having a dominant wavelength in the wavelength range from blue to green including blue-green can emit light with a reduced difference in brightness felt by humans in scotopic vision and photopic vision while maintaining excellent visibility that appears bright in both scotopic vision and photopic vision. The dominant wavelength, luminous flux, chromaticity coordinates (x, y) in the xy chromaticity coordinate system of the CIE1931 chromaticity diagram described later, and the total spectral radiant flux of the light emitted from the light emitting device can be measured using an optical measurement system that combines a spectrophotometer (e.g., PMA-11, manufactured by Hamamatsu Photonics K.K.) and an integrating sphere.

[0020] Another embodiment of the light emitting device is a light emitting device comprising a light emitting element having a dominant wavelength in the range of 400 nm or more and 500 nm or less, and a wavelength conversion member arranged on the light emission side of the light emitting element and containing a rare earth aluminate phosphor having a composition represented by formula (I) described below, wherein the light emitting device emits light having a dominant wavelength in the range of 475 nm or more and 500 nm or less, and has a melanopic ratio of 3.4 or less derived from formula (2) below.

[0021]

number

[0022] In formula (2), in the wavelength range of 380 nm to 730 nm, "Lamp × Circadian" is the circadian response included in the spectral distribution of the light-emitting device, "Lamp × Visual" is the luminosity response included in the spectral distribution of the light-emitting device, "Lamp" is the spectral distribution of the light-emitting device, "Circadian" is the sensitivity curve of the intrinsically photosensitive retinal ganglion cell (ipRGC), which is a photoreceptor in the mammalian retina, "Visual" is the luminosity curve in human photopic vision, and "1.218" is a constant (lux factor). The spectral distribution (emission spectrum) of the light-emitting device can be measured using a light measurement system that combines a spectrophotometer (e.g., PMA-11, manufactured by Hamamatsu Photonics Co., Ltd.) and an integrating sphere. For "Visual," the standard spectral luminous efficiency V(λ) for human photopic vision defined by the CIE can be used (Visual = V(λ)).

[0023] In addition to cone cells and rods, the presence of intrinsically photosensitive retinal neurons (ipRGCs) containing the visual pigment melanopsin has been discovered in the photoreceptor cells (photoreceptor cells) of the human retina. These ipRGCs respond to light stimuli by themselves, and also receive input from cones and rods to respond to light stimuli, thereby influencing the human circadian rhythm. Figure 2 shows the sensitivity curve (circadian action curve) of ipRGCs and the visual sensitivity curve of human photopic vision. The peak wavelength of the visual sensitivity curve of human photopic vision is 555 nm, and the melanopsin output from ipRGCs has a peak sensitivity wavelength of around 480 nm to 500 nm. Melanopsin is also involved in the secretion and suppression of melatonin, a sleep-promoting hormone. Furthermore, the melanopsin output of ipRGCs is also projected to the imaging pathway from the lateral geniculate body to the visual cortex, which transmits visual information, and may affect the visual system, such as image perception. For example, the melanopic ratio is a value derived from the spectral distribution of a light-emitting device, the sensitivity curve (absorbance) of ipRGCs, and the luminosity curve in human photopic vision. The higher the melanopic ratio, the stronger the stimulation given to the human circadian rhythm. If the melanopic ratio of the light emitted from a light-emitting device is 3.4 or less, it is thought that it can evoke a specific image as a signal color that indicates a specific state of a device, such as when charging, without significantly affecting the human circadian rhythm.

[0024] The melanopic ratio of the light emitted from the light-emitting device may be 3.3 or less, or may be 3.2 or less, and is preferably 1.4 or more, and more preferably 1.5 or more. If the melanopic ratio of the light emitted from the light-emitting device is within the range of 1.4 to 3.4, it is considered that the light can evoke a specific image as a light that emits a signal color that indicates a specific state, such as during charging, without significantly affecting human circadian rhythm.

[0025] The light emitting device has chromaticity coordinates (x, y) in the xy chromaticity coordinate system of the CIE1931 chromaticity diagram, with a first point being (x=0.0082, y=0.5384), a second point being (x=0.1096, y=0.0868), a third point being (x=0.210, y=0.190), and a fourth point being (x=0.260, y=0.380), and a first line connecting the first point and the second point and a second line connecting the second point and the third point are intersected by a first line. point It is preferable that the light emitting device emits light within an area A1 defined by a second line connecting the third point and the fourth point, a third line connecting the third point and the fourth point, and a fourth line connecting the fourth point and the first point. FIG. 3 shows the area A1 in the xy chromaticity coordinate system of the CIE 1931 chromaticity diagram. It is preferable that the light emitting device emits light within the area A1 surrounded by the lines connecting the first point and the second point, the second point and the third point, the third point and the fourth point, and the fourth point and the first point in FIG. 3. The light emitting device emits light within the area A1 in FIG. 3, and the light within the area A1 has a dominant wavelength within a range of 475 nm or more and 500 nm or less, and exhibits an emission color of blue to green including blue-green.

[0026] The light emitting device has chromaticity coordinates (x, y) in the xy chromaticity coordinate system of the CIE1931 chromaticity diagram, with a first point being (x=0.0350, y=0.4127), a second point being (x=0.0800, y=0.2149), a third point being (x=0.2150, y=0.2106), and a fourth point being (x=0.2550, y=0.3550), and a first line connecting the first point and the second point and a second line connecting the second point and the third point are intersected by a first line. point It is preferable that the light emitting device emits light within an area A2 defined by a second line connecting the third point and the fourth point, a third line connecting the third point and the fourth point, and a fourth line connecting the fourth point and the first point. FIG. 4 shows the area A2 in the xy chromaticity coordinate system of the CIE 1931 chromaticity diagram. It is preferable that the light emitting device emits light within the area A2 surrounded by the lines connecting the first point and the second point, the second point and the third point, the third point and the fourth point, and the fourth point and the first point in FIG. 4. The light emitting device emits light within the area A2 in FIG. 4, and the light within the area A2 has a dominant wavelength within a range of 475 nm or more and 500 nm or less, and exhibits an emission color of blue to blue-green.

[0027] The light emitting device has chromaticity coordinates (x, y) in the xy chromaticity coordinate system of the CIE1931 chromaticity diagram, with a first point being (x=0.1825, y=0.3252), a second point being (x=0.1550, y=0.2149), a third point being (x=0.1930, y=0.2106), and a fourth point being (x=0.2205, y=0.3209), and a first line connecting the first point and the second point and a line connecting the second point and the third point being (x=0.1825, y=0.3252) are defined as follows: point It is more preferable that the light emitting device emits light within an area A3 defined by a second line connecting the third point and the fourth point, a third line connecting the third point and the fourth point, and a fourth line connecting the fourth point and the first point. FIG. 5 shows the area A3 in the xy chromaticity coordinate system of the CIE 1931 chromaticity diagram. It is preferable that the light emitting device emits light within the area A3 surrounded by the lines connecting the first point and the second point, the second point and the third point, the third point and the fourth point, and the fourth point and the first point in FIG. 5. The light emitting device emits light within the area A3 in FIG. 5, and the light within the area A3 has a dominant wavelength within a range of 475 nm or more and 500 nm or less, and exhibits an emission color of blue to blue-green.

[0028] 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 to 531 nm to the integral value Ia in the wavelength range of 380 nm to 780 nm is preferably in the range of 0.6 to 0.95, more preferably in the range of 0.65 to 0.94, even more preferably in the range of 0.70 to 0.93, and particularly preferably in the range of 0.75 to 0.92. When the integral value ratio Ib / Ia in the emission spectrum of the light emitting device is in the range of 0.6 to 0.95, it is considered that the light emitting device emits light having a dominant wavelength in the wavelength range of blue to green including blue-green, and can emit light with reduced difference in brightness felt by humans in both scotopic and photopic vision while maintaining excellent visibility that appears bright in both scotopic and photopic vision. The emission spectrum of the light emitting device, the integral value Ia in the wavelength range of 380 nm to 780 nm in the measured emission spectrum, and the integral value Ib in the wavelength range of 380 nm to 531 nm in the measured emission spectrum can be measured using an optical measurement system that combines a spectrophotometer (e.g., PMA-11, manufactured by Hamamatsu Photonics K.K.) and an integrating sphere. The integral ratio Ib / Ia can be calculated from the measured integral values ​​Ia and Ib.

[0029] Light emitting element The light-emitting element may have a composition formula of In X Al Y Ga 1-X-Y A light-emitting diode (LED) chip or a laser diode (LD: Laser Diode) chip, which is a semiconductor light-emitting element using a nitride-based semiconductor represented by N (0≦X, 0≦Y, X+Y≦1), can be used, and it is preferable to use an LED chip.

[0030] The light emitting element has a dominant wavelength in the range of 400 nm to 500 nm, and preferably the dominant wavelength of the light emitted from the light emitting element is in the range of 420 nm to 495 nm, and more preferably in the range of 430 nm to 490 nm.

[0031] 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 has an emission peak wavelength in the range of 390 nm or more and 495 nm or less, even more preferably has an emission peak wavelength in the range of 400 nm or more and 490 nm or less, and particularly preferably has an emission peak wavelength in the range of 420 nm or more and 490 nm or less.

[0032] 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 may be formed on the same side of the light emitting element or on different sides. The light emitting element may be flip-chip mounted.

[0033] Rare Earth Aluminate Phosphors The rare earth aluminate phosphor contained in the light emitting device has a composition represented by the following formula (I). (Lu 1-p-n Ln p Ce n )3(Al 1-m Ga m ) 5k O 12 (I) (In formula (I), Ln is at least one rare earth element selected from the group consisting of Y, La, Gd, and Tb, and k, m, n, and p satisfy 0.95≦k≦1.05, 0.05≦m≦0.70, 0.002≦n≦0.050, and 0≦p≦0.30, respectively.)

[0034] The rare earth aluminate having the composition represented by formula (I) is excited by light from a light-emitting element having a dominant wavelength in the range of 400 nm or more and 500 nm or less, and converts the wavelength of the light emitted from the light-emitting element, thereby emitting light having a dominant wavelength in the range of 475 nm or more and 500 nm or less from the light-emitting device.

[0035] In the formula (I), the molar ratio of Ce is the product of the variable n and 3. The variable n is 0.002 or more, may be 0.003 or more, may be 0.004 or more, may be 0.005 or more, may be 0.050 or less, may be 0.045 or less, may be 0.040 or less, may be 0.035 or less, or may be 0.030 or less. Ce acts as an activator for the rare earth aluminate phosphor. In the formula (I), the variable n may be in the range of 0.002 to 0.045 (0.002≦n≦0.045), 0.002 to 0.040 (0.002≦n≦0.040), 0.003 to 0.040 (0.003≦n≦0.040), or 0.003 to 0.035 (0.003≦n≦0.035). The molar ratio of Ce in 1 mole of the rare earth aluminate phosphor having the composition represented by the formula (I) is preferably in the range of 0.006 to 0.15. When the molar ratio of Ce is in the range of 0.006 to 0.15, the luminescence luminance is high and a desired luminescence color can be obtained.

[0036] In the formula (I), the molar ratio of Ga is the product of the variable m, the variable k in the range of 0.95 to 1.05, and 5. The variable m is in the range of 0.05 to 0.70 (0.05≦m≦0.70), may be in the range of 0.10 to 0.70 (0.10≦m≦0.70), or may be in the range of 0.10 to 0.60 (0.10≦m≦0.60). The variable m may be 0.20 or more, 0.30 or more, 0.55 or less, or 0.50 or less. The molar ratio of Ga in 1 mole of the rare earth aluminate phosphor having the composition represented by the formula (I) is preferably in the range of 0.2375 to 3.15. In the formula (I), by adjusting the molar ratio of Ga, which is expressed together with Al as the product of the variables k, m, and 5, so that the variable m is within the range of 0.05 to 0.70, the emission peak wavelength of the phosphor can be changed, and when used in a light emitting device, a desired emission color can be obtained.

[0037] In the formula (I), Ln is at least one rare earth element selected from the group consisting of Y, La, Gd, and Tb. The rare earth element Ln acts as a co-activator together with the activator Ce. Ln may be at least one rare earth element selected from the group consisting of Y, La, and Gd, or Ln may be Y. In the formula (I), the molar ratio of the at least one rare earth element Ln selected from the group consisting of Y, La, Gd, and Tb is the product of the variable p and 3. In the formula (I), the rare earth element Ln may not be included. In the formula (I), the variable p may be in the range of 0 to 0.20 (0≦p≦0.20). In the formula (I), the variable p may be in the range of 0.001 to 0.20 (0.001≦p≦0.20).

[0038] In the formula (I), m, n, and p preferably satisfy 0.10≦m≦0.70, 0.002≦n≦0.040, and 0≦p≦0.20, respectively. By adjusting the molar ratio of Ce acting as an activator, the molar ratio of Ga, and, if necessary, the molar ratio of the rare earth element Ln, a desired emission color can be obtained when used in a light emitting device.

[0039] Method for producing rare earth aluminate phosphor The rare earth aluminate phosphor can be produced by heat-treating a raw material mixture of the compounds containing each element, which are oxides containing each element of Lu, Ce, Al, Ga, and at least one rare earth element Ln selected from the group consisting of Y, La, Gd, and Tb as necessary, or carbonates or hydroxides that become oxides by thermal decomposition. A raw material mixture obtained by mixing only the raw materials before heat treatment may be called a first raw material mixture. The rare earth aluminate phosphor can also be produced by using a coprecipitate containing all or part of each element constituting the rare earth aluminate phosphor. For example, a coprecipitate containing the elements can be obtained by adding an aqueous solution of an alkali or carbonate to an aqueous solution containing at least one element selected from the group consisting of Lu, Ce, Al, Ga, and at least one element selected from the group consisting of Y, La, Gd, and Tb as necessary. The rare earth aluminate phosphor can also be produced by drying and heat-treating the coprecipitate. The rare earth aluminate phosphor may be produced by using a flux, and the flux is preferably a fluoride containing the element constituting the rare earth aluminate phosphor. The flux may be at least one selected from the group consisting of BaF2, AlF3, and CeF3. The flux is preferably used in an amount of 0.1 to 10 parts by mass, and may be used in an amount of 0.5 to 8.0 parts by mass, relative to 100 parts by mass of the raw material mixture (or the first raw material mixture). The mixture of the raw material mixture (or the first raw material mixture) and the flux may be referred to as the first mixture.

[0040] The heat treatment temperature is preferably in the range of 1000° C. to 1800° C., and may be in the range of 1100° C. to 1750° C., 1200° C. to 1700° C., 1300° C. to 1650° C., or 1400° C. to 1600° C. For example, an electric furnace, a gas furnace, or the like may be used for the heat treatment.

[0041] The heat treatment atmosphere is preferably a reducing atmosphere. The heat treatment can be carried out in a reducing atmosphere containing at least one of nitrogen, hydrogen, a reducing compound, and ammonia. In a highly reducing atmosphere, the raw material mixture becomes highly reactive, and a fired product can be obtained by firing under atmospheric pressure without applying pressure. In addition, by heat treating the raw material mixture in a highly reducing atmosphere, tetravalent Ce (Ce 4+ ) is trivalent Ce(Ce 3+ ) to obtain a fired product in which the proportion of trivalent Ce that contributes to luminescence in the fired product is increased.

[0042] The heat treatment time varies depending on the temperature rise rate, the heat treatment atmosphere, etc., but is preferably 1 hour or more, more preferably 2 hours or more, and even more preferably 3 hours or more after the heat treatment temperature is reached, and is preferably within 20 hours, more preferably within 18 hours, and even more preferably within 15 hours.

[0043] In the method for producing a rare earth aluminate phosphor, the fired product obtained by heat-treating the raw material mixture is called the first fired product, and the first fired product, a compound containing Lu, a compound containing Ce, a compound containing Al, a compound containing Ga, and a compound containing the rare earth element Ln as required are mixed, and the second fired product obtained by the second heat treatment may be obtained as a rare earth aluminate phosphor. A mixture of a compound containing Lu, a compound containing Ce, a compound containing Al, a compound containing Ga, and a compound containing the rare earth element Ln as required, not including the first fired product, is called the first raw material mixture, and heat-treating the first raw material mixture may be called the first heat treatment. A mixture of a flux mixed into the first raw material mixture is also called the first mixture. A raw material mixture of a compound containing Lu, a compound containing Ce, a compound containing Al, a compound containing Ga, and a compound containing the rare earth element Ln as required, other than the first fired product, which is mixed with the first fired product, is also called the second raw material mixture. The content of the first fired product in the total amount of the second fired product and the second raw material mixture is preferably in the range of 10% by mass to 90% by mass, and may be in the range of 20% by mass to 80% by mass. The mixture of the first fired product and the second raw material mixture may contain a flux. A mixture containing the first fired product, the second raw material mixture, and optionally a flux is also called a second mixture. When a flux is contained, it is preferably used in the range of 0.1 parts by mass to 10 parts by mass, and may be used in the range of 0.5 parts by mass to 8.0 parts by mass, relative to 100 parts by mass of the second raw material mixture.

[0044] The first heat treatment and the second heat treatment can be performed at the same heat treatment temperature, heat treatment atmosphere, and heat treatment time as described above. The fired product obtained after the first heat treatment is also called the first fired product. The fired product obtained after the second heat treatment is also called the second fired product.

[0045] The first fired product and the second fired product may be subjected to a dispersion treatment, which may be performed by wet dispersion, wet sieving, dehydration, drying, dry sieving, or the like. As a solvent for wet dispersion, for example, deionized water may be used. The time for wet dispersion varies depending on the solid dispersion medium and solvent used, but is preferably 30 minutes or more, more preferably 60 minutes or more, even more preferably 90 minutes or more, even more preferably 120 minutes or more, and is preferably within 420 minutes. The dispersion treatment can improve the dispersibility of the rare earth aluminate phosphor in the manufacturing process of the light emitting device.

[0046] The first or second calcined product after the dispersion treatment may be subjected to an acid treatment in which the product is brought into contact with an acidic solution or a base treatment in which the product is brought into contact with a basic solution. By bringing the first or second calcined product into contact with an acidic or basic solution, decomposition products contained in the first or second calcined product that have been decomposed during the heat treatment can be removed. The acidic substance contained in the acidic solution may be an inorganic acid such as hydrofluoric acid, nitric acid, or hydrochloric acid, or may be hydrogen peroxide. The basic substance contained in the basic solution may be a hydroxide containing an alkali metal or ammonia. The time for which the first or second calcined product is brought into contact with the acidic or basic solution is, for example, 10 minutes to 30 hours, preferably 30 minutes to 25 hours, and more preferably 1 hour to 25 hours, in order to remove thermal decomposition products contained in the first or second calcined product. Furthermore, in order to efficiently remove decomposition products contained in the first or second fired product, the temperature at which the acidic or basic solution is brought into contact with the first or second fired product is preferably from room temperature (about 20° C.) to 300° C., more preferably from 30° C. to 200° C., and even more preferably from 40° C. to 150° C. After the acid treatment or base treatment, a step of washing the first or second fired product with a liquid medium may be included.

[0047] The resulting first-fired product and second-fired product are rare earth aluminate phosphors having the composition represented by the above formula (I).

[0048] In addition to the rare earth aluminate phosphor having a composition represented by formula (I), the light emitting device preferably includes at least one phosphor selected from the group consisting of a halosilicate phosphor having a composition represented by formula (II), a β-sialon phosphor having a composition represented by formula (III), an oxynitride phosphor having a composition represented by formula (IV), an alkaline earth metal aluminate phosphor having a composition represented by formula (V), an alkaline earth metal sulfide phosphor having a composition represented by formula (VI), a first silicate phosphor having a composition represented by formula (VII), a second silicate phosphor having a composition represented by formula (VIII), a third silicate phosphor or germanate phosphor having a composition represented by formula (IX), and a fourth silicate phosphor having a composition represented by formula (X). (Ca,Sr,Ba)8MgSi4O 16 (F,Cl,Br)2:Eu (II) S 6-z Al z O z N 8-z :Eu(0 <z≦4.2) (III) BaSi2O2N2:Eu (IV) Sr4Al 14 O 25 :Eu (V) (Sr,Ca,Ba)Ga2S4:Eu (VI) (Ba,Sr,Ca)2SiO4:Eu (VII) (Ba,Sr)ZrSiO9:Eu (VIII) Ca3Sc2(Si,Ge)3O 12 :Ce (IX) (ALi3SiO4)n:Eu (A is at least one element selected from the group consisting of Li, Na, K, Rb and Cs, and n is an integer from 1 to 8) (X)

[0049] In this specification, in the composition formula showing the composition of the phosphor, a plurality of elements separated by a comma (,) means that at least one of the plurality of elements is contained in the composition, and two or more of the plurality of elements may be contained in combination. In addition, in the formula showing the composition of the phosphor, the part before the colon (:) represents the elements constituting the host crystal and their molar ratio, and the part after the colon (:) represents an activating element. It is understood that the molar amount of the activating element written after the colon (:) does not have to be the same molar amount as the molar amount of the element written before the colon. The "molar ratio" represents the molar amount of an element in 1 mole of the composition of the phosphor.

[0050] A halosilicate phosphor having a composition represented by the formula (II), a β-sialon phosphor having a composition represented by the formula (III), an oxynitride phosphor having a composition represented by the formula (IV), an alkaline earth metal aluminate phosphor having a composition represented by the formula (V), an alkaline earth metal sulfide phosphor having a composition represented by the formula (VI), a first silicate phosphor having a composition represented by the formula (VII), a second silicate phosphor having a composition represented by the formula (VIII), a third silicate phosphor having a composition represented by the formula (IX), or a germane At least one phosphor selected from the group consisting of a rare earth aluminate phosphor and a fourth silicate phosphor having a composition represented by the formula (X) is excited by light from a light-emitting element having a dominant wavelength in the range of 400 nm or more and 500 nm or less, and, together with the rare earth aluminate phosphor having a composition represented by the formula (I), converts the wavelength of the light from the light-emitting element to emit from the light-emitting device light having a dominant wavelength in the range of 475 nm or more and 500 nm or less, and having an S / P ratio represented by the formula (1) of 6.5 or less or a melanopic ratio represented by the formula (2) of 3.4 or less.

[0051] Wavelength conversion material The wavelength conversion member preferably includes a wavelength conversion body containing a phosphor and a light-transmitting material, and more preferably includes a light-transmitting body on which the wavelength conversion body is disposed. The wavelength conversion body preferably includes a phosphor and a light-transmitting material described later. The wavelength conversion body may be formed in a plate-like, sheet-like, or layer-like shape. The wavelength conversion member may include a wavelength conversion body in a form other than a plate-like, sheet-like, or layer-like shape. A plate-like wavelength conversion sintered body can also be used as the wavelength conversion member. The plate-like wavelength conversion sintered body can be obtained, for example, by the method disclosed in JP 2018-172628 A using a mixture of a phosphor and an inorganic oxide as a raw material. For example, aluminum oxide (Al2O3) can be used as the inorganic oxide.

[0052] In the light emitting device, the rare earth aluminate phosphor having the composition represented by formula (I) and the phosphor other than the rare earth aluminate phosphor preferably constitute a wavelength converter together with a light-transmitting material. The wavelength converter may constitute a wavelength conversion member together with a light-transmitting body. The wavelength converter preferably contains the rare earth aluminate phosphor having the composition represented by formula (I) in a range of 1 part by mass to 800 parts by mass, more preferably in a range of 10 parts by mass to 750 parts by mass, and even more preferably in a range of 15 parts by mass to 700 parts by mass, per 100 parts by mass of the light-transmitting material. The light emitting device includes a wavelength conversion member having a wavelength converter containing the rare earth aluminate phosphor represented by formula (I) excited by the light emitted by the light emitting element, and by disposing the wavelength conversion member on the light emission side of the light emitting element, the light from the light emitting element can be efficiently wavelength-converted by the rare earth aluminate phosphor having the composition represented by formula (I) contained in the wavelength converter.

[0053] In the rare earth aluminate phosphor having a composition represented by the formula (I), when the molar ratio of Ce represented by the product of the variable n and 3 is within the range of 0.018 to 0.150, and the variable n is 0.006≦n≦0.050, the content of the rare earth aluminate phosphor having a composition represented by the formula (I) in the wavelength converter may be within the range of 10 parts by mass to 800 parts by mass, 20 parts by mass to 780 parts by mass, 30 parts by mass to 750 parts by mass, or 40 parts by mass to 700 parts by mass, relative to 100 parts by mass of the translucent material.

[0054] The wavelength converter may contain two or more rare earth aluminate phosphors having different compositions, each of which has a composition represented by formula (I). In the rare earth aluminate phosphors having different compositions, when the molar ratio of Ce represented by the product of the variable n and 3 in the composition represented by formula (I) is in the range of 0.018 to 0.150, and the variable n is 0.006≦n≦0.050, the total content of the two or more rare earth aluminate phosphors contained in the wavelength converter may be in the range of 10 to 800 parts by mass, 20 to 780 parts by mass, 30 to 750 parts by mass, or 40 to 700 parts by mass, relative to 100 parts by mass of the translucent material.

[0055] In the rare earth aluminate phosphor having a composition represented by the formula (I), when the molar ratio of Ga is in the range of 0.5 to 3.0 and the molar ratio of Ce is in the range of 0.015 to 0.040, the content of the rare earth aluminate phosphor contained in the wavelength converter may be in the range of 20 to 700 parts by mass, 40 to 650 parts by mass, 60 to 600 parts by mass, or 80 to 560 parts by mass, relative to 100 parts by mass of the translucent material. In the rare earth aluminate phosphor having a composition represented by the formula (I), when the molar ratio of Ga is in the range of 0.5 to 3.0 and the variable k is in the range of 0.95 to 1.05 (0.95≦k≦1.05), the variable m is in the range of 0.095 to 0.631 (0.095≦m≦0.631). In the rare earth aluminate phosphor having the composition represented by formula (I), when the molar ratio of Ce is within the range of 0.015 to 0.040, the variable n is within the range of 0.005 to 0.013 (0.005≦n≦0.013). In the rare earth aluminate phosphor having a composition represented by the formula (I), when the molar ratio of Ga is in the range of 0.5 to 2.0 and the molar ratio of Ce is in the range of 0.018 to 0.040, the content of the rare earth aluminate phosphor contained in the wavelength converter may be in the range of 20 to 500 parts by mass, 30 to 400 parts by mass, or 40 to 300 parts by mass, relative to 100 parts by mass of the translucent material. In the rare earth aluminate phosphor having a composition represented by the formula (I), when the molar ratio of Ga is in the range of 0.5 to 2.0 and the variable k is in the range of 0.95 to 1.05 (0.95≦k≦1.05), the variable m is in the range of 0.095 to 0.421 (0.095≦m≦0.421). In the rare earth aluminate phosphor having the composition represented by formula (I), when the molar ratio of Ce is within the range of 0.018 to 0.040, the variable n is within the range of 0.006 to 0.013 (0.006≦n≦0.013).

[0056] The wavelength converter may contain, in addition to the rare earth aluminate phosphor represented by formula (I), at least one phosphor selected from the group consisting of a halosilicate phosphor having a composition represented by formula (II), a β-sialon phosphor having a composition represented by formula (III), an oxynitride phosphor having a composition represented by formula (IV), an alkaline earth metal aluminate phosphor having a composition represented by formula (V), an alkaline earth metal sulfide phosphor having a composition represented by formula (VI), a first silicate phosphor having a composition represented by formula (VII), a second silicate phosphor having a composition represented by formula (VIII), a third silicate phosphor or germanate phosphor having a composition represented by formula (IX), and a fourth silicate phosphor having a composition represented by formula (X). The wavelength converter may contain a total amount of phosphor within the range of 1 part by mass or more and 900 parts by mass or less, 10 parts by mass or more and 850 parts by mass or less, or 15 parts by mass or more and 800 parts by mass or less, per 100 parts by mass of the translucent material.

[0057] Translucent material The translucent material may be at least one selected from the group consisting of resin, glass, and inorganic material. The resin is preferably at least one selected from the group consisting of epoxy resin, silicone resin, phenol resin, and polyimide resin. The inorganic material may be at least one selected from the group consisting of aluminum oxide and aluminum nitride. In addition to the phosphor and the translucent material, the wavelength converter may contain a filler, a colorant, and a light diffusing material as necessary. Examples of the filler include silicon oxide, barium titanate, titanium oxide, and aluminum oxide. The content of other components other than the phosphor and the translucent material contained in the wavelength converter can be in the range of 0.01 parts by mass to 100 parts by mass, or may be in the range of 0.1 parts by mass to 80 parts by mass, or may be in the range of 0.5 parts by mass to 75 parts by mass, based on 100 parts by mass of the translucent material, in terms of the total content of the other components.

[0058] Translucent body The wavelength conversion member may include a light-transmitting body. The light-transmitting body may be 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 may be any thickness that does not reduce mechanical strength during the manufacturing process and can sufficiently support the wavelength conversion body.

[0059] Light emitting device - First configuration example A configuration example of a light emitting device is shown. FIG. 6A is a schematic plan view of a light emitting device 100 of a first configuration example. FIG. 6B is a schematic cross-sectional view of the light emitting device 100 shown in FIG. 6A along the line VI-VI'. The light emitting device 100 includes a light emitting element 10 having a main wavelength in the range of 400 nm to 500 nm, and a wavelength conversion member 30 including a wavelength converter 31 containing at least one phosphor that is excited by light from the light emitting element 10 to emit light, and a light-transmitting body 32 in which the wavelength converter 31 is arranged. The light emitting element 10 is flip-chip mounted on a substrate 70 via bumps that are conductive members 60. The wavelength converter 31 of the wavelength conversion member 30 is provided on the light emitting surface of the light emitting element 10 via an adhesive layer 80. The light emitting element 10 and the wavelength conversion member 30 have their sides covered by a covering member 90 that reflects light. The wavelength converter 31 contains a phosphor that is excited by light from the light emitting element 10 and has at least one emission peak wavelength in a specific wavelength range. The wavelength converter 31 may contain two or more phosphors having different emission peak wavelengths in different wavelength ranges. The light emitting element 10 can emit light by receiving power from the outside of the light emitting device 100 through wiring and a conductive member 60 formed on the substrate 70. The light emitting device 100 may include a semiconductor element 50 such as a protective element for protecting the light emitting element 10 from destruction due to application of an excessive voltage. The covering member 90 is provided so as to cover the semiconductor element 50, for example. Each member used in the light emitting device will be described below. For details, the disclosure of JP 2014-112635 A may be referred to.

[0060] substrate The substrate is preferably made of an insulating material that is difficult to transmit light from the light emitting element or external light. Examples of the substrate material include ceramics such as aluminum oxide and aluminum nitride, and resins such as phenol resin, epoxy resin, polyimide resin, bismaleimide triazine resin (BT resin), and polyphthalamide (PPA) resin. Ceramics are preferred as a substrate material because of their high heat resistance.

[0061] adhesive layer An adhesive layer is interposed between the light emitting element and the wavelength conversion member, and fixes 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. The material constituting the adhesive layer is preferably at least one resin selected from the group consisting of epoxy resin, silicone resin, phenol resin, and polyimide resin.

[0062] Semiconductor Device Examples of semiconductor elements that are provided in a light-emitting device as necessary include transistors for controlling light-emitting elements and protective elements for preventing the light-emitting elements from being destroyed or their performance from deteriorating due to application of an excessive voltage, such as Zener diodes.

[0063] Covering material It is preferable to use an insulating material as the material for the covering member. More specifically, it is possible to use phenol resin, epoxy resin, bismaleimide triazine resin (BT resin), polyphthalamide (PPA) resin, and silicone resin. Colorants, phosphors, and fillers may be added to the covering member as necessary.

[0064] Conductive material The conductive member may be a bump, and the material of the bump may be Au or an alloy thereof, and other conductive members may be eutectic solder (Au-Sn), Pb-Sn, lead-free solder, or the like.

[0065] Manufacturing method of light emitting device - First configuration example An example of a method for manufacturing a light emitting device will be described. For details, refer to, for example, the disclosures of JP 2014-112635 A or JP 2017-117912 A. The method for manufacturing a light emitting device preferably includes a step of arranging a light emitting element, a step of arranging a semiconductor element as necessary, a step of forming a wavelength conversion member including a wavelength converter, a step of bonding the light emitting element and the wavelength conversion member, and a step of forming a covering member.

[0066] Light emitting element arrangement process In the step of arranging the light emitting element, the light emitting element is arranged on a substrate and mounted thereon. The light emitting element and the semiconductor element are mounted on the substrate by, for example, flip chip mounting.

[0067] Forming process of wavelength conversion member including wavelength conversion body In the step of forming a wavelength conversion member containing a wavelength converter, the wavelength conversion member may be obtained by forming a plate-shaped, sheet-shaped or layer-shaped wavelength conversion member on one surface of a light-transmitting body by a printing method, an adhesive method, a compression molding method or an electrodeposition method. For example, the printing method can print a composition for a wavelength conversion member containing a phosphor and a resin serving as a binder or a solvent on one surface of a light-transmitting body to form a wavelength conversion member containing a wavelength conversion member.

[0068] Bonding process between light emitting element and wavelength conversion material In the step of adhering the light emitting element and the wavelength conversion member, the wavelength conversion member is opposed to the light emitting surface of the light emitting element, and the wavelength conversion member is bonded onto the light emitting element by an adhesive layer.

[0069] Forming process of the covering member In the step of forming the covering member, the side surfaces of the light emitting element and the wavelength conversion member except for the light emitting surface are covered with the composition for the covering member, and a covering member is formed on the side surfaces of the light emitting element and the wavelength conversion member except for the light emitting surface. This covering member is for reflecting light emitted from the light emitting element, and is formed so as to cover the side surfaces without covering the light emitting surface of the wavelength conversion member and to embed the semiconductor element.

[0070] In this manner, the light emitting device shown in FIGS. 6A and 6B can be manufactured.

[0071] Light emitting device - second configuration example Fig. 7 is a schematic cross-sectional view of a light emitting device 200 of a second configuration example. The light emitting device 200 is the same as the light emitting device 100, except that the light emitting device 200 includes a wavelength conversion member 30 made of a wavelength converter 31 containing at least one phosphor that emits light when excited by light from the light emitting element 10. In Fig. 7, the same members as those in the light emitting device 100 are given the same reference numerals. The wavelength conversion member 30 may be made of the wavelength converter 31 without including the translucent body 32.

[0072] Manufacturing method of light emitting device - second configuration example The manufacturing method of the light emitting device of the second configuration example can be the same as the manufacturing method of the light emitting device of the first configuration example, except that in the wavelength conversion member forming step, a wavelength conversion member made of a wavelength converter is formed. The wavelength converter is formed in advance into a plate-like, sheet-like or layer-like shape by curing a composition for wavelength converters containing a phosphor and a translucent material, and is then cut into individual pieces of a size that can be arranged on the light emitting element, to prepare a wavelength conversion member made of a plate-like, sheet-like or layer-like wavelength converter. In this manner, the light emitting device of the second configuration example can be manufactured. As described above, the wavelength conversion member can also be a plate-like wavelength conversion sintered body.

[0073] Light emitting device - Third configuration example FIG. 8 is a schematic cross-sectional view of a light emitting device 300 of a third configuration example. The light emitting device 300 includes, for example, a molded body 41, a light emitting element 11, and a wavelength conversion member 33. The molded body 41 is formed by integrally molding a first lead 51, a second lead 52, and a resin part 42 containing a thermoplastic resin or a thermosetting 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, respectively, via wires 63. The light emitting element 11 is covered with a wavelength conversion member 33. The wavelength conversion member 33 includes a phosphor 21 that converts the wavelength of light from the light emitting element 11, and a translucent material. The phosphor 21 is excited by light from the light emitting element to have at least one emission peak wavelength in a specific wavelength range, and may include two or more phosphors having different wavelength ranges of emission peak wavelengths. The first lead 51 and the second lead 52 connected to a pair of positive and negative electrodes of the light emitting element 11 are partially exposed toward the outside of the package constituting the light emitting device 300. Through the first lead 51 and the second lead 52, power can be supplied from the outside to cause the light emitting device 300 to emit light.

[0074] The light-transmitting material used in the wavelength conversion member may be the same as the light-transmitting material used in the wavelength conversion member of the first or second configuration example. In addition, the wavelength conversion member may contain a filler, a colorant, and a light diffusing material as necessary, similar to the wavelength conversion members of the first and second configuration examples.

[0075] Manufacturing method of light emitting device - Third configuration example A method for manufacturing a light emitting device of the third configuration example will be described. For details, the disclosure of JP 2010-062272 A can be referred to. The method for manufacturing a light emitting device preferably includes a molded body preparation step, a light emitting element arrangement step, a wavelength conversion member composition arrangement step, and a resin package formation step. When an aggregate molded body having a plurality of recesses is used as the molded body, a singulation step of separating the resin packages of each unit area may be included after the resin package formation step.

[0076] In the step of preparing a molded body, a plurality of leads are integrally molded using a thermosetting resin or a thermoplastic resin to prepare a molded body having a recess having a side surface and a bottom surface. The molded body may be a molded body made of an aggregate base including a plurality of recesses. In the step of arranging the light-emitting element, the light-emitting element is arranged on the bottom surface of the recess of the molded body, and the positive and negative electrodes of the light-emitting element are connected to the first lead and the second lead by wires. In the step of placing the composition for a wavelength conversion member, the composition for a wavelength conversion member is placed in the recess of the molded body. In the resin package molding step, the composition for wavelength conversion member arranged in the recess of the molded body is cured to form a resin package, and a light emitting device is manufactured. When a molded body made of an aggregate base having a plurality of recesses is used, after the resin package forming step, the aggregate base having a plurality of recesses is separated into each resin package of each unit area in a singulation step, and individual light emitting devices are manufactured. In this manner, the light emitting device of the third configuration example shown in FIG. 8 can be manufactured. EXAMPLES

[0077] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0078] Rare earth aluminate phosphor A Raw material preparation Lutetium oxide (Lu2O3), cerium oxide (CeO2), aluminum oxide (Al2O3), and gallium oxide (Ga2O3) were used as raw materials, and raw materials consisting of each compound were prepared so that the elements Lu, Ce, Al, and Ga contained in each compound satisfied the following composition to obtain a raw material mixture. 7.0 mass% of barium fluoride (BaF2) was added as a flux relative to the total amount of 100 mass%, and the raw materials were mixed in a ball mill to obtain a mixture. The raw materials were charged with the following composition: (Lu 0.987 Ce 0.012 )3(Al 0.9 Ga 0.1 )5O 12 It was prepared so that Heat Treatment The resulting mixture was placed in an alumina crucible and heat-treated in a reducing atmosphere at 1600° C. for 10 hours to obtain a fired product. Distributed Processing The obtained fired material, alumina balls as a dispersion medium, and deionized water were placed in a container and dispersed for 4 hours while rotating. After that, coarse particles were removed using a wet sieve. Then, sedimentation classification was performed to remove fine particles. Acid cleaning treatment The fired product obtained by sedimentation classification was washed with an aqueous hydrochloric acid solution having a hydrochloric acid concentration of 17% by mass, then washed with water, separated and dried.

[0079] Rare Earth Aluminate Phosphor B Rare earth aluminate phosphor B was obtained in the same manner as for rare earth aluminate phosphor A, except that the raw materials were prepared so that the elements Lu, Ce, Al, and Ga satisfied the following composition. 0.987 Ce 0.013 )3(Al 0.8 Ga 0.2 )5O 12 It was prepared so that

[0080] Rare Earth Aluminate Phosphor C Rare earth aluminate phosphor C was obtained in the same manner as for rare earth aluminate phosphor A, except that the raw materials were prepared so that the elements Lu, Ce, Al, and Ga satisfied the following composition. 0.987 Ce 0.013 )3(Al 0.7 Ga 0.3 )5O 12 It was prepared so that

[0081] Rare Earth Aluminate Phosphor D Rare earth aluminate phosphor D was obtained in the same manner as for rare earth aluminate phosphor A, except that the raw materials were prepared so that the elements Lu, Ce, Al, and Ga satisfied the following composition. 0.987 Ce 0.013 )3(Al 0.6 Ga 0.4 )5O 12 It was prepared so that

[0082] Rare Earth Aluminate Phosphor E Raw materials were prepared so that the elements Lu, Ce, Al, and Ga fulfilled the following composition. Rare earth aluminate phosphor E was obtained in the same manner as rare earth aluminate phosphor A, except that the heat treatment was carried out at 1500°C for 10 hours. The raw materials were prepared so that the composition of each compound was as follows: (Lu 0.995 Ce 0.005 )3(Al 0.6 Ga 0.4 )5O 12 It was prepared so that

[0083] Rare Earth Aluminate Phosphor F Rare earth aluminate phosphor F was obtained in the same manner as for rare earth aluminate phosphor E, except that the raw materials were prepared so that the elements Lu, Ce, Al, and Ga satisfied the following composition. 0.995 Ce 0.005 )3(Al 0.5 Ga 0.5 )5O 12 It was prepared so that

[0084] Rare Earth Aluminate Phosphor G Rare earth aluminate phosphor G was obtained in the same manner as for rare earth aluminate phosphor E, except that the raw materials were prepared so that the elements Lu, Ce, Al, and Ga satisfied the following composition. 0.995 Ce 0.005 )3(Al 0.4 Ga 0.6 )5O 12 It was prepared so that

[0085] Rare Earth Aluminate Phosphor H Rare earth aluminate phosphor H was obtained in the same manner as for rare earth aluminate phosphor E, except that the heat treatment was performed at 1500°C for 10 hours in an air atmosphere. 0.995 Ce 0.005 )3(Al 0.6 Ga 0.4 )5O 12 It was prepared so that

[0086] Rare Earth Aluminate Phosphors I Preparation of raw materials (first mixture) Lutetium oxide (Lu2O3), cerium oxide (CeO2), aluminum oxide (Al2O3), and gallium oxide (Ga2O3) were used as raw materials, and raw materials consisting of each compound were prepared so that the elements Lu, Ce, Al, and Ga contained in each compound satisfied the following composition. 7.0 mass% of barium fluoride (BaF2) was added as a flux relative to the total amount of 100 mass%, and the raw materials were mixed in a ball mill to obtain a first mixture. The raw materials were charged with the following composition: (Lu 0.995 Ce 0.005 )3(Al 0.6 Ga 0.4 )5O 12 It was prepared so that First heat treatment The resulting first mixture was placed in an alumina crucible and heat-treated in a reducing atmosphere at 1500° C. for 10 hours to obtain a first fired product. second mixture The obtained first fired product, lutetium oxide (Lu2O3), cerium oxide (CeO2), aluminum oxide (Al2O3), and gallium oxide (Ga2O3) were used as raw materials, and raw materials consisting of each compound were prepared so that the elements Lu, Ce, Al, and Ga contained in the first fired product and each compound satisfied the above composition, and a second raw material mixture was obtained by adding 7.0 mass% barium fluoride (BaF2) as a flux to the total amount of 100 mass%. The first fired product and the second raw material mixture were mixed using a ball mill so that the mass ratio was 7:3, and a second mixture was obtained. Second heat treatment The obtained second mixture was placed in an alumina crucible and heat-treated in a reducing atmosphere at 1500°C for 10 hours to obtain a second fired product. This second fired product was subjected to a dispersion treatment and an acid washing treatment in the same manner as for the rare earth aluminate A to obtain rare earth aluminate phosphor I.

[0087] Rare Earth Aluminate Phosphor J Rare earth aluminate phosphor J was obtained in the same manner as for rare earth aluminate phosphor A, except that the raw materials were prepared so that the elements Lu, Ce, Al, and Ga satisfied the following composition. 0.993 Ce 0.007 )3(Al 0.6 Ga 0.4 )5O 12 It was prepared so that

[0088] Rare Earth Aluminate Phosphor K Rare earth aluminate phosphor K was obtained in the same manner as for rare earth aluminate phosphor A, except that the raw materials were prepared so that the elements Lu, Ce, Al, and Ga satisfied the following composition. 0.992 Ce 0.008 )3(Al 0.6 Ga 0.4 )5O 12 It was prepared so that

[0089] Rare Earth Aluminate Phosphor L Rare earth aluminate phosphor L was obtained in the same manner as for rare earth aluminate phosphor A, except that the raw materials were prepared so that the elements Lu, Ce, Al, and Ga satisfied the following composition. 0.990 Ce 0.010 )3(Al 0.6 Ga 0.4 )5O 12 It was prepared so that

[0090] Rare Earth Aluminate Phosphor M Rare earth aluminate phosphor M was obtained in the same manner as for rare earth aluminate phosphor A, except that the raw materials were prepared so that the elements Lu, Ce, Al, and Ga satisfied the following composition. 0.988 Ce 0.012 )3(Al 0.6 Ga 0.4 )5O 12 It was prepared so that

[0091] Rare Earth Aluminate Phosphor N Rare earth aluminate phosphor N was obtained in the same manner as for rare earth aluminate phosphor A, except that the raw materials were prepared so that the elements Lu, Ce, Al, and Ga satisfied the following composition. 0.987 Ce 0.013 )3(Al 0.6 Ga 0.4 )5O 12 It was prepared so that

[0092] Evaluation of rare earth aluminate phosphors. The obtained rare earth aluminate phosphor was evaluated as follows. The evaluation results are shown in Table 1. In Table 1, Ga (molar ratio) and Ce (molar ratio) are the molar ratios of each element in the charged composition.

[0093] Luminous properties The emission characteristics of each phosphor were measured. The emission characteristics of the phosphors were measured by irradiating each phosphor with an excitation light having a wavelength of 420 nm using a quantum efficiency measuring device (QE-2000, manufactured by Otsuka Electronics Co., Ltd.) and measuring the emission spectrum at room temperature (25°C ± 5°C). From the emission spectrum of each phosphor, the chromaticity coordinates (x, y) and luminance (%) in the chromaticity coordinate system of the CIE chromaticity diagram were calculated for each phosphor.

[0094] [Table 1]

[0095] Examples 1-1 to 1-3 A light emitting device was manufactured using rare earth aluminate A. For the manufacturing method of the light emitting device, the disclosure of JP 2010-062272 A can be referred to. Specifically, a molded body having a first lead, a second lead, and a recess having a bottom surface and a side surface was prepared. A light emitting element using a nitride semiconductor having a main wavelength of 455 nm was prepared, and the light emitting element was placed on the bottom surface of the recess and connected to the first lead and the second lead by wire. A composition for wavelength converter containing rare earth aluminate phosphor A in the amount shown in Table 2 (Example 1-1: 20 parts by mass, Example 1-2: 40 parts by mass, Example 1-3: 60 parts by mass) per 100 parts by mass of silicone resin as a light transmissive material was prepared, and the composition for wavelength converter was filled in the recess of the molded body. The composition for wavelength converter was cured by heating at 150° C. for 4 hours, and a wavelength conversion member made of a wavelength converter covering the light emitting element was formed to form a resin package, and a light emitting device was manufactured.

[0096] Examples 2-1 to 2-3 A light emitting device was manufactured using rare earth aluminate phosphor B. A composition for a wavelength converter containing rare earth aluminate phosphor B in the amount shown in Table 2 (Example 2-1: 20 parts by mass, Example 2-2: 40 parts by mass, Example 2-3: 60 parts by mass) was prepared, and a light emitting device was manufactured in the same manner as in Example 1-1, except that this composition for a wavelength converter was used.

[0097] Examples 3-1 to 3-3 A light emitting device was manufactured using rare earth aluminate phosphor C. A composition for a wavelength converter containing rare earth aluminate phosphor C in the amount shown in Table 2 (Example 3-1: 40 parts by mass, Example 3-2: 60 parts by mass, Example 3-3: 80 parts by mass) was prepared, and a light emitting device was manufactured in the same manner as in Example 1-1, except that this composition for a wavelength converter was used.

[0098] Comparative Example 4-1, Examples 4-2 to 4-5 A light emitting device was manufactured using rare earth aluminate phosphor D. A composition for a wavelength converter containing rare earth aluminate phosphor D in the amount shown in Table 2 (Comparative Example 4-1: 20 parts by mass, Example 4-2: 40 parts by mass, Example 4-3: 60 parts by mass, Example 4-4: 90 parts by mass, Example 4-5: 120 parts by mass) was prepared, and a light emitting device was manufactured in the same manner as in Example 1-1, except that this composition for a wavelength converter was used.

[0099] Comparative Example 1 A light emitting element using a nitride semiconductor with a dominant wavelength of 454 nm was prepared, and a light emitting device of the first embodiment was manufactured in the same manner as in Example 1-1, except that no phosphor was used.

[0100] Comparative Example 2 A light emitting element using a nitride semiconductor with a dominant wavelength of 484 nm was prepared, and a light emitting device of the first embodiment was manufactured in the same manner as in Example 1-1, except that no phosphor was used.

[0101] Comparative Example 3 A light emitting element using a nitride semiconductor with a dominant wavelength of 495 nm was prepared, and a light emitting device of the first embodiment was manufactured in the same manner as in Example 1-1, except that no phosphor was used.

[0102] The following evaluations were carried out for each light-emitting element and each light-emitting device. The evaluation results for each light-emitting device are shown in Table 2.

[0103] Evaluation of light-emitting element (dominant wavelength of light-emitting element) For each of the light-emitting elements used in the examples and comparative examples, the chromaticity coordinates (x, y) in the chromaticity coordinate system of the CIE 1931 chromaticity diagram were measured using an optical measurement system combining a spectrophotometer (PMA-11, Hamamatsu Photonics K.K.) and an integrating sphere, and the chromaticity coordinates (x, y) of the white light in the CIE 1931 chromaticity diagram (x=0.3333, y=0.3333) and the chromaticity coordinates (x, y) of the emitted color of each light-emitting element were calculated. E , y E ) was connected by a straight line, and the wavelength at the point where the extended line intersected with the spectral locus was determined as the dominant wavelength.

[0104] Light emitting device evaluation Luminous flux of the light-emitting device, luminous flux ratio, radiant flux (spectral total radiant flux), chromaticity coordinates (x, y) For each light-emitting device, the luminous flux, radiant flux (spectral total radiant flux: mW), and chromaticity coordinates (x, y) in the chromaticity coordinate system of the CIE1931 chromaticity diagram were determined using an optical measurement system that combines a spectrophotometer (PMA-11, Hamamatsu Photonics K.K.) and an integrating sphere.

[0105] Dominant wavelength of the light emitting device λd The dominant wavelength of each light-emitting device was determined by drawing a line between the chromaticity coordinates (x = 0.3333, y = 0.3333) of white light on the CIE 1931 chromaticity diagram and the chromaticity coordinates (x, y) of the emitted color of each light-emitting device, and finding the wavelength at the point where this extended line intersects with the spectral locus.

[0106] S / P ratio For each light emitting device, the S / P ratio, which is the ratio of the luminous flux in scotopic vision to the luminous flux in photopic vision, was calculated based on the above formula (1).

[0107] Emission spectrum of light emitting device The emission spectrum of each light-emitting device was measured at room temperature (25°C ± 5°C) using an optical measurement system that combined a spectrophotometer (PMA-11, Hamamatsu Photonics K.K.) and an integrating sphere. The relative emission spectrum of each light-emitting device was calculated with the maximum emission intensity set to 1.

[0108] Melanopic Ratio The melanopic ratio was calculated based on the above formula (2) from the spectral distribution of each light-emitting device, the sensitivity curve (absorbance) of ipRGC, and the luminosity curve in human photopic vision.

[0109] Ratio of integrals of emission spectrum Ib / Ia In the relative emission spectrum of each light-emitting device, the ratio Ib / Ia of the integral Ib in the wavelength range of 380 nm to 531 nm to the integral Ia in the wavelength range of 380 nm to 780 nm was determined.

[0110] [Table 2]

[0111] The light emitting device of each Example emitted light having a dominant wavelength in the range of 475 nm to 500 nm, and had an S / P ratio, which is the ratio of the luminous flux in scotopic vision to the luminous flux in photopic vision, of 6.5 or less. Even when emitting light having a dominant wavelength in the wavelength range of blue to green, including blue-green, the light emitting device of each Example reduced the difference between the luminous flux in a dark place and the luminous flux in a bright place, and appeared bright in both scotopic and photopic vision, and was considered to be able to maintain excellent visibility.

[0112] The light emitting device of each Example emitted light having a dominant wavelength in the range of 475 nm to 500 nm, and had a melanopic ratio of 3.4 or less. The light emitting device of each Example was considered to be unlikely to have a significant effect on human circadian rhythm, and to be capable of emitting light having a dominant wavelength in the wavelength range from blue to green, including blue-green, which can evoke a specific image as a signal color indicating a specific state of a device, such as during charging.

[0113] The light having a dominant wavelength within the range of 475 nm to 500 nm emitted from the light emitting device of each Example exhibited an emission color within region A1 shown in Fig. 3 and region A2 shown in Fig. 4 in the xy chromaticity coordinate system of the CIE 1931 chromaticity diagram. The light emitting devices of Examples 3-2, 4-2, 4-3, 4-4, and 4-5 exhibited an emission color of blue to blue-green in region A3 shown in Fig. 5, within region A1 and region A2.

[0114] The light emitting devices of each embodiment have an integral value ratio Ib / Ia in the range of 0.6 or more and 0.95 or less, and are considered to be able to emit light that reduces the difference in brightness perceived by humans in both scotopic and photopic vision, while maintaining excellent visibility that appears bright in both scotopic and photopic vision.

[0115] The light emitting device of Comparative Example 1 emitted light having a dominant wavelength of less than 475 nm, and had an S / P ratio exceeding 6.5, and it was assumed that the light emitting device of Comparative Example 1 may be perceived as being too bright when viewed in a dark place. In addition, the light emitting device of Comparative Example 1 emitted light having a dominant wavelength of less than 475 nm, and had a melanopic ratio exceeding 3.4, and it was considered that the light emitting device of Comparative Example 1 may affect the human circadian rhythm. In addition, the light emitting device of Comparative Example 1 emitted light having a dominant wavelength of less than 475 nm, and did not exhibit the emission color in the region A1 shown in FIG. 3. In addition, the light emitting device of Comparative Example 1 had an integral value ratio Ib / Ia exceeding 0.95, and it was assumed that the light emitting device of Comparative Example 1 may be perceived as being too bright in a dark place.

[0116] The light emitting device of Comparative Example 2 emitted light having a dominant wavelength in the range of 475 nm to 500 nm, but the S / P ratio exceeded 6.5, and it was assumed that the light may be perceived as too bright when viewed in a dark place. In addition, the light emitting device of Comparative Example 2 emitted light having a dominant wavelength in the range of 475 nm to 500 nm, and the melanopic ratio exceeded 3.4, and it was considered that the light emitting device of Comparative Example 2 may affect the human circadian rhythm. In addition, the light emitting device of Comparative Example 2 emitted light having a dominant wavelength in the range of 475 nm to 500 nm, and exhibited the emission color in the region A1 shown in FIG. 3, but did not exhibit the emission color in the region A2 shown in FIG. 4 and the region A3 shown in FIG. 5. In addition, the light emitting device of Comparative Example 2 had an integral value ratio Ib / Ia exceeding 0.95, and it was assumed that the light emitting device of Comparative Example 2 may be perceived as too bright in a dark place.

[0117] The light emitting device of Comparative Example 3 emitted light having a dominant wavelength in the range of 475 nm to 500 nm, but the S / P ratio exceeded 6.5, and it was assumed that the light may be perceived as too bright when viewed in a dark place. In addition, the light emitting device of Comparative Example 3 emitted light having a dominant wavelength in the range of 475 nm to 500 nm, and the melanopic ratio exceeded 3.4, and it was considered that the light may affect the human circadian rhythm. In addition, the light emitting device of Comparative Example 3 emitted light having a dominant wavelength in the range of 475 nm to 500 nm, and this light exhibited the emission color in the region A1 shown in FIG. 3 and the region A2 shown in FIG. 4, but did not exhibit the emission color in the region A3 shown in FIG. In addition, the light emitting device of Comparative Example 3 had an integral value ratio Ib / Ia exceeding 0.95, and it was assumed that the light may be perceived as too bright in a dark place.

[0118] In the light emitting device of Comparative Example 4-1, the molar ratio of Ga in the composition of rare earth aluminate phosphor D contained in the wavelength conversion member is relatively high, and the molar ratio of Ce is also relatively high. As a result, the emission peak wavelength of rare earth aluminate phosphor D changes compared to phosphors with a low molar ratio of Ga, and when the content of rare earth aluminate phosphor D is low, light having a dominant wavelength in the range of 475 nm or more and 500 nm or less is not emitted.

[0119] Comparative Examples 5-1 to 5-2, Examples 5-3 to 5-7 A light emitting device was manufactured using rare earth aluminate phosphor E. A composition for a wavelength converter containing rare earth aluminate phosphor E in the amount shown in Table 3 (Comparative Example 5-1: 20 parts by mass, Comparative Example 5-2: 40 parts by mass, Example 5-3: 60 parts by mass, Example 5-4: 90 parts by mass, Example 5-5: 120 parts by mass, Example 5-6: 200 parts by mass, Example 5-7: 280 parts by mass) was prepared, and a light emitting device was manufactured in the same manner as in Example 1-1, except that this composition for a wavelength converter was used.

[0120] Comparative Examples 6-1 to 6-4, Examples 6-5 to 6-9 A light emitting device was manufactured using rare earth aluminate phosphor F. A composition for a wavelength converter containing rare earth aluminate phosphor F in the amount shown in Table 3 (Comparative Example 6-1: 20 parts by mass, Comparative Example 6-2: 40 parts by mass, Comparative Example 6-3: 60 parts by mass, Comparative Example 6-4: 100 parts by mass, Example 6-5: 200 parts by mass, Example 6-6: 300 parts by mass, Example 6-7: 400 parts by mass, Example 6-8: 450 parts by mass, Example 6-9: 550 parts by mass) was prepared, and a light emitting device was manufactured in the same manner as in Example 1-1, except that this composition for a wavelength converter was used.

[0121] Comparative Examples 7-1 to 7-4, Examples 7-5 to 7-11 A light emitting device was manufactured using the rare earth aluminate phosphor G. A composition for a wavelength converter containing the rare earth aluminate phosphor G in the amount shown in Table 3 (Comparative Example 7-1: 20 parts by mass, Comparative Example 7-2: 40 parts by mass, Comparative Example 7-3: 60 parts by mass, Comparative Example 7-4: 150 parts by mass, Example 7-5: 250 parts by mass, Example 7-6: 350 parts by mass, Example 7-7: 450 parts by mass, Example 7-8: 560 parts by mass, Example 7-9: 600 parts by mass, Example 7-10: 650 parts by mass, Example 7-11: 700 parts by mass) was prepared, and a light emitting device was manufactured in the same manner as in Example 1-1, except that this composition for a wavelength converter was used.

[0122] Comparative Examples 8-1 to 8-4, Examples 8-5 to 8-8 A light emitting device was manufactured using rare earth aluminate phosphor H. A composition for a wavelength converter containing rare earth aluminate phosphor H in the amount shown in Table 3 (Comparative Example 8-1: 20 parts by mass, Comparative Example 8-2: 40 parts by mass, Comparative Example 8-3: 60 parts by mass, Comparative Example 8-4: 100 parts by mass, Example 8-5: 200 parts by mass, Example 8-6: 300 parts by mass, Example 8-7: 400 parts by mass, Example 8-8: 450 parts by mass) was prepared, and a light emitting device was manufactured in the same manner as in Example 1-1, except that this composition for a wavelength converter was used.

[0123] Comparative Examples 9-1 to 9-2, Examples 9-3 to 9-6 A light emitting device was manufactured using the rare earth aluminate phosphor I. A composition for a wavelength converter containing the rare earth aluminate phosphor I in the amount shown in Table 3 (Comparative Example 9-1: 20 parts by mass, Comparative Example 9-2: 40 parts by mass, Example 9-3: 60 parts by mass, Example 9-4: 120 parts by mass, Example 9-5: 200 parts by mass, Example 9-6: 300 parts by mass) was prepared, and a light emitting device was manufactured in the same manner as in Example 1-1, except that this composition for a wavelength converter was used.

[0124] Each light emitting device was evaluated in the same manner as in Example 1-1. The results are shown in Table 3.

[0125] [Table 3]

[0126] The light emitting device of each Example emitted light having a dominant wavelength in the range of 475 nm to 500 nm, and had an S / P ratio, which is the ratio of the luminous flux in scotopic vision to the luminous flux in photopic vision, of 6.5 or less. Even when emitting light having a dominant wavelength in the wavelength range of blue to green including blue-green, the light emitting device of each Example reduced the difference between the luminous flux in a dark place and the luminous flux in a bright place, appeared bright in both scotopic and photopic vision, and was considered to be able to maintain excellent visibility and reduce the difference in brightness perceived by humans.

[0127] The light emitting device of each Example emitted light having a dominant wavelength in the range of 475 nm to 500 nm, and had a melanopic ratio of 3.4 or less. It was considered that the light emitting device of each Example could emit light having a dominant wavelength in the wavelength range from blue to green, including blue-green, which can evoke a specific image as a signal color indicating a specific state of a device, such as during charging, without significantly affecting human circadian rhythm.

[0128] The light having a dominant wavelength within the range of 475 nm to 500 nm emitted from the light emitting device of each Example exhibited an emission color within region A1 shown in Fig. 3 and region A2 shown in Fig. 4 in the xy chromaticity coordinate system of the CIE 1931 chromaticity diagram. The light emitting devices of Example 5-5, Example 5-6, Examples 6-6 to 6-9, Examples 7-7 to 7-11, Examples 8-5 to 8-8, and Example 9-5 exhibited an emission color of blue to blue-green in region A3 shown in Fig. 5, within region A1 and region A2.

[0129] The light emitting devices of each embodiment have an integral value ratio Ib / Ia in the range of 0.6 or more and 0.95 or less, and are considered to be able to emit light that reduces the difference in brightness perceived by humans in both scotopic and photopic vision, while maintaining excellent visibility that appears bright in both scotopic and photopic vision.

[0130] In each of the light emitting devices of Comparative Examples 5-1 to 5-2, 6-1 to 6-4, 7-1 to 7-4, 8-1 to 8-3, and 9-1, the molar ratio of Ga is relatively high and the molar ratio of Ce is low in the composition of the rare earth aluminate phosphors E to I contained in the wavelength conversion member, so that the luminance is low, and when the content of the rare earth aluminate phosphors E to I is low, light having a dominant wavelength of less than 475 nm is emitted, and the S / P ratio exceeds 6.5, and it is assumed that when viewed in a dark place, it may be felt that it is too bright. In addition, each of the light emitting devices of Comparative Examples 5-1 to 5-2, 6-1 to 6-4, 7-1 to 7-4, 8-1 to 8-3, and 9-1 emits light having a dominant wavelength of less than 475 nm, and the melanopic ratio exceeds 3.4, and there is a possibility that it may affect the human circadian rhythm. In each of the light-emitting devices of Comparative Example 8-4 and Comparative Example 9-2, the molar ratio of Ga in the composition of the rare earth aluminate phosphor H or I contained in the wavelength conversion member is relatively high, so that the emission peak wavelength of the rare earth aluminate phosphor H or I changes compared to a phosphor with a lower molar ratio of Ga, and when the content of the rare earth aluminate phosphor H or I is low, light having a dominant wavelength in the range of 475 nm or more and 500 nm or less is not emitted.

[0131] Example 10-1, Comparative Examples 10-2 to 10-3 A light emitting device having the embodiment shown in FIGS. 6A and 6B was manufactured. In the process of arranging the light-emitting element, a ceramic substrate made of aluminum nitride was used as the substrate. The light-emitting element used was a light-emitting element in which nitride-based semiconductor layers with a dominant wavelength of 450 nm were laminated. The size of the light-emitting element was a roughly square shape of about 1.0 mm square in plan view, and the thickness was about 0.11 mm. The light-emitting element was arranged so that the light-emitting surface was on the substrate side, and flip-chip mounted with bumps using a conductive member made of Au. In addition, a semiconductor element was flip-chip mounted with a gap between the light-emitting element and bumps using a conductive member made of Au.

[0132] In the process of forming a wavelength converter including a wavelength conversion member, a rare earth aluminate phosphor A was used. A composition for a wavelength converter was prepared containing rare earth aluminate phosphor A in the amount shown in Table 4 (Example 10-1: 100 parts by mass, Comparative Example 10-2: 150 parts by mass, Comparative Example 10-3: 200 parts by mass) relative to 100 parts by mass of silicone resin as a light-transmitting material, and 15 parts by mass of aluminum oxide as a filler. As a light-transmitting body, a light-transmitting body made of borosilicate glass, approximately 0.15 mm larger in length and width than the planar shape of the light-emitting element, approximately 1.15 mm square in planar shape, and approximately 0.10 mm thick was prepared. The composition for a wavelength converter was printed by a printing method on one surface of the approximately square shape of the light-transmitting body, and heated at 180°C for 2 hours to harden the composition for a wavelength converter, forming a layered wavelength converter with a thickness of approximately 80 μm, and a wavelength conversion member in which a layered or plate-shaped wavelength converter and a light-transmitting body are integrated was formed.

[0133] In the process of bonding the light-emitting element and the wavelength conversion member, one surface of the wavelength conversion member, which has a planar shape of approximately 1.15 mm square, and one surface of the light-emitting element, which has a planar shape of approximately 1.0 mm square, were bonded together using an adhesive containing silicone resin to form an adhesive layer between the light-emitting element and the wavelength conversion member.

[0134] In the step of forming a covering member, a composition for a covering member was prepared, which contained dimethyl silicone resin and titanium oxide particles having an average particle size (catalog value) of 0.28 μm, and contained 30 parts by mass of titanium oxide particles per 100 parts by mass of dimethyl silicone resin. The side surfaces of the light emitting element and the wavelength conversion member including the wavelength converter and the light transmitting body arranged on the substrate were covered with the composition for a covering member, and the composition for a covering member was filled so that the semiconductor element was completely embedded in the composition for a covering member, and the composition for a covering member was cured to form a covering member, and a resin package was formed, thereby producing a light emitting device.

[0135] Examples 11-1 to 11-2, Comparative Example 11-3 A light emitting device was manufactured by mixing rare earth aluminate phosphor A and rare earth aluminate phosphor H in a weight ratio of 50:50. A composition for a wavelength converter containing a mixture of rare earth aluminate phosphor A and rare earth aluminate phosphor H in the amount shown in Table 4 (Example 11-1: 200 parts by mass, Example 11-2: 300 parts by mass, Comparative Example 11-3: 500 parts by mass) was prepared, and a light emitting device was manufactured in the same manner as in Example 10-1, except that this composition for a wavelength converter was used.

[0136] Examples 12-1 to 12-3 A light emitting device was manufactured using rare earth aluminate phosphor H. A composition for a wavelength converter containing rare earth aluminate phosphor H in the amount shown in Table 4 (Example 12-1: 400 parts by mass, Example 12-2: 500 parts by mass, Example 12-3: 600 parts by mass) was prepared, and a light emitting device was manufactured in the same manner as in Example 10-1, except that this composition for a wavelength converter was used.

[0137] [Table 4]

[0138] The light emitting device of each Example emitted light having a dominant wavelength in the range of 475 nm to 500 nm, and had an S / P ratio, which is the ratio of the luminous flux in scotopic vision to the luminous flux in photopic vision, of 6.5 or less. Even when emitting light having a dominant wavelength in the wavelength range of blue to green including blue-green, the light emitting device of each Example reduced the difference between the luminous flux in a dark place and the luminous flux in a bright place, appeared bright in both scotopic and photopic vision, and was considered to be able to maintain excellent visibility and reduce the difference in brightness perceived by humans.

[0139] The light emitting device of each Example emitted light having a dominant wavelength in the range of 475 nm to 500 nm, and had a melanopic ratio of 3.4 or less. The light emitting device of each Example emitted light having a dominant wavelength in the wavelength range from blue to green, including blue-green, which is unlikely to have a significant effect on human circadian rhythms and can evoke a specific image as a signal color indicating a specific state of a device, such as when charging.

[0140] The light having a dominant wavelength within the range of 475 nm to 500 nm emitted from the light emitting device of each Example exhibited an emission color within region A1 shown in Fig. 3 and region A2 shown in Fig. 4 in the xy chromaticity coordinate system of the CIE 1931 chromaticity diagram. The light emitting device of Example 12-3 exhibited an emission color of blue to blue-green in region A3 shown in Fig. 5, among regions A1 and A2.

[0141] The light emitting devices of each embodiment have an integral value ratio Ib / Ia in the range of 0.6 or more and 0.95 or less, and are considered to be able to emit light that reduces the difference in brightness perceived by humans in both scotopic and photopic vision, while maintaining excellent visibility that appears bright in both scotopic and photopic vision.

[0142] In each of the light-emitting devices of Comparative Examples 10-2 to 10-3 and Comparative Example 11-3, the brightness of the rare earth aluminate phosphor A contained in the wavelength converter was high, and when the content of rare earth aluminate phosphor was too high, light having a dominant wavelength exceeding 500 nm was emitted, and no light having a dominant wavelength within the range of 475 nm or more and 500 nm or less was emitted. [Industrial Applicability]

[0143] A 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 a vehicle, a display device, a lighting fixture, a display, and the like. [Explanation of symbols]

[0144] 10, 11: light-emitting element, 21: phosphor, 30, 33: wavelength conversion member, 31: wavelength conversion body, 32: light-transmitting body, 41: molded body, 42: resin part, 50: semiconductor element, 51: first lead, 52: second lead, 60: conductive member, 63: wire, 70: substrate, 80: adhesive layer, 90: covering member, 100, 200, 300: light-emitting device.

Claims

1. A light emitting element having a dominant wavelength in the range of 400 nm to 500 nm; a wavelength conversion member disposed on a light emission side of the light emitting element, the wavelength conversion member including a rare earth aluminate phosphor having a composition represented by the following formula (I): (L １－ｐ－ｎ Ln ｐ Ce ｎ ) ３ (AS １－ｍ G ｍ ) ５ｋ O １２ (I) (In formula (I), Ln is at least one rare earth element selected from the group consisting of Y, La, Gd, and Tb, and k, m, n, and p satisfy 0.95≦k≦1.05, 0.05≦m≦0.70, 0.002≦n≦0.050, and 0≦p≦0.30, respectively.) Emitting light having a dominant wavelength in the range of 475 nm or more and 500 nm or less; A light emitting device having an S / P ratio, which is a ratio of luminous flux in scotopic vision to luminous flux in photopic vision, derived from the following formula (1) of 6.5 or less. (In formula (1), the constant K is 6831 (lm / W), the constant K' is 1700 (lm / W), and within the wavelength λ range of 360 nm or more and 830 nm or less, V(λ) is the standard spectral luminous efficiency for human photopic vision, V'(λ) is the standard spectral luminous efficiency for human scotopic vision, and Φ ｅ (λ) is the spectral total radiant flux of the light emitted from the light-emitting device.)

2. A light emitting element having a dominant wavelength in the range of 400 nm to 500 nm; a wavelength conversion member disposed on a light emission side of the light emitting element, the wavelength conversion member including a rare earth aluminate phosphor having a composition represented by the following formula (I): (L １－ｐ－ｎ Ln ｐ Ce ｎ ) ３ (AS １－ｍ G ｍ ) ５ｋ O １２ (I) (In formula (I), Ln is at least one rare earth element selected from the group consisting of Y, La, Gd, and Tb, and k, m, n, and p satisfy 0.95≦k≦1.05, 0.05≦m≦0.70, 0.002≦n≦0.050, and 0≦p≦0.30, respectively.) Emitting light having a dominant wavelength in the range of 475 nm or more and 500 nm or less; A light-emitting device having a melanopic ratio, calculated from the following formula (2), of 3.4 or less. (In formula (2), in the wavelength range of 380 nm or more and 730 nm or less, "Lamp x Circadian" is a circadian response included in the spectral distribution of the light emitting device, "Lamp x Visual" is a luminosity response included in the spectral distribution of the light emitting device, "Lamp" is the spectral distribution of the light emitting device, "Circadian" is a sensitivity curve of intrinsic photosensitive retinal ganglion cells, which are photoreceptors in the retina of mammals, "Visual" is a luminosity curve in human photopic vision, and "1.218" is a constant (lux factor).)

3. 3. The light emitting device according to claim 1, wherein in an xy chromaticity coordinate system of the CIE 1931 chromaticity diagram, a first point is (x=0.0082, y=0.5384), a second point is (x=0.1096, y=0.0868), a third point is (x=0.210, y=0.190), and a fourth point is (x=0.260, y=0.380), and the light emitting device emits light within an area A1 defined by a first line connecting the first point and the second point, a second line connecting the second point and the third point, a third line connecting the third point and the fourth point, and a fourth line connecting the fourth point and the first point, the light emitting device according to claim 1, wherein the light emitting device emits light within an area A1 defined by a first line connecting the first point and the second point, a second line connecting the second point and the third point, a third line connecting the third point and the fourth point, and a fourth line connecting the fourth point and the first point, the light emitting device according to claim 1,

4. The light emitting device of claim 1 , wherein the S / P ratio is 6.0 or less.

5. The light emitting device according to claim 1 , wherein the S / P ratio is 3.0 or more.

6. The light emitting device of claim 2 , wherein the melanopic ratio is 1.4 or greater.

7. 7. The light emitting device according to claim 1, wherein in an emission spectrum of the light emitting device, a ratio Ib / Ia of an integral Ib of an emission spectrum in a wavelength range of 380 nm to 531 nm to an integral Ia of the emission spectrum in a wavelength range of 380 nm to 780 nm is in the range of 0.6 to 0.

95.

8. 8. The light emitting device according to claim 1, wherein in an xy chromaticity coordinate system of the CIE 1931 chromaticity diagram, a first point is (x=0.0350, y=0.4127), a second point is (x=0.0800, y=0.2149), a third point is (x=0.2150, y=0.2106), and a fourth point is (x=0.2550, y=0.3550), and the light emitting device emits light within an area A2 defined by a first line connecting the first point and the second point, a second line connecting the second point and the third point, a third line connecting the third point and the fourth point, and a fourth line connecting the fourth point and the first point, the light emitting device according to claim 1, wherein the light emitting device emits light within an area A2 defined by a first line connecting the second point and the third point, a second line connecting the second point and the third point, a third line connecting the third point and the fourth point, and a fourth line connecting the fourth point and the first point, the light emitting device according to claim 1,

9. 9. The light emitting device according to claim 1, wherein in an xy chromaticity coordinate system of the CIE 1931 chromaticity diagram, a first point is (x=0.1825, y=0.3252), a second point is (x=0.1550, y=0.2149), a third point is (x=0.1930, y=0.2106), and a fourth point is (x=0.2205, y=0.3209), and the light emitting device emits light within an area A3 defined by a first line connecting the first point and the second point, a second line connecting the second point and the third point, a third line connecting the third point and the fourth point, and a fourth line connecting the fourth point and the first point, the light emitting device according to claim 1, wherein the light emitting device emits light within an area A3 defined by a first line connecting the first point and the second point, a second line connecting the second point and the third point, a third line connecting the third point and the fourth point, and a fourth line connecting the fourth point and the first point, the light emitting device according to claim 1,

10. 10. The light emitting device according to claim 1 , further comprising at least one phosphor selected from the group consisting of a rare earth aluminate phosphor having a composition represented by formula (I), a halosilicate phosphor having a composition represented by formula (II), a β-sialon phosphor having a composition represented by formula (III), an oxynitride phosphor having a composition represented by formula (IV), an alkaline earth metal aluminate phosphor having a composition represented by formula (V), an alkaline earth metal sulfide phosphor having a composition represented by formula (VI), a first silicate phosphor having a composition represented by formula (VII), a second silicate phosphor having a composition represented by formula (VIII), a third silicate phosphor or germanate phosphor having a composition represented by formula (IX), and a fourth silicate phosphor having a composition represented by formula (X). (1,Sr,BL) ８ Yes ４ O １６ (F, Cl, Br) ２ :Eu (II) Yes ６－ｚ Al ｚ O ｚ N ８－ｚ :Eu (0<z≦4.2) (III) 2019 ２ O ２ N ２ :Eu (IV) Sr ４ Al １４ O ２５ :Eu (V) (Sr,Ca,Ba)Ga ２ S ４ :Eu (VI) (Ba,Sr,Ca) ２ 2019 ４ :Eu (VII) (Ba,Sr)ZrSi ３ O ９ :Eu (VIII) Ca ３ Sc ２ (Yes,Ge) ３ O １２ :Ce (IX) (ALi ３ SiO ４ ) n: Eu (A is at least one element selected from the group consisting of Li, Na, K, Rb and Cs, and n is an integer from 1 to 8.) (X)

11. 11. The light emitting device according to claim 1, wherein k, m, n, and p in the formula (I) satisfy 0.95≦k≦1.05, 0.3≦m≦0.5, 0.002≦n≦0.04, and 0≦p≦0.20, respectively.

Images