Light emitting device, headlamp, and vehicle having the same

Abstract

The invention provides a light-emitting device capable of reducing glare and improving durability, a headlamp and a vehicle provided with the same. The light-emitting device is provided with: a light-emitting element having an emission peak wavelength within the range of 400-490 nm; and a wavelength conversion member. The wavelength conversion member includes a first phosphor having an emission peak wavelength in a range of 480 nm or more and less than 580 nm, and a second phosphor having an emission peak wavelength in a range of 580 nm or more and 680 nm or less and having a composition different from that of the first phosphor, and the light emitting device emits light having a first luminance ratio Ls / L of 0.9 or less. The first luminance ratio Ls / L is a ratio of a first effective radiance Ls of light emitted by the light-emitting device taking into account a photopic vision standard relative visibility curve of a person specified by CIE and spectral sensitivity of an S-cone of the person, to a luminance L of light emitted by the light-emitting device taking into account the photopic vision standard relative visibility curve of the person. The first phosphor contains a rare earth aluminate phosphor having a composition represented by formula (1A).

Description

Technical Field

[0001] The present invention relates to a light emitting device, a headlamp and a vehicle equipped with the same. Background Art

[0002] The headlights of road transport vehicles such as motor four-wheeled vehicles and motor two-wheeled vehicles, tractors such as land preparation, transporting and loading machinery, or excavators such as digging machinery can use lamps such as halogen lamps, HID lamps (High-Intensity Discharge Lamp), light-emitting devices using semiconductor light-emitting elements as excitation light sources, and the like. For example, one or more headlights for automobiles are installed symmetrically on the left and right sides of the front at a position lower than the driver's viewpoint. The headlights are equipped with lamps for high beams (driving headlights) and low beams (oncoming headlights), and are set in a way that they can be switched. The high beam illuminates a relatively far front area, such as about 100 meters, and the low beam illuminates a portion slightly lower than the high beam, such as about 40 meters in front.

[0003] For example, Patent Document 1 discloses a vehicle headlamp, which includes a first lamp unit that lights up in a low-beam mode and a first lamp unit and a second lamp unit that light up simultaneously in a high-beam mode. Patent Document 1 discloses that a white LED emitting light at a correlated color temperature of 4000K to 6500K is used as a light source as the first lamp unit, and a metal halide lamp that is one of HID lamps emitting light at a correlated color temperature of 4000K to 5000K is used as a light source as the second lamp unit.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2005-141917 Summary of the invention

[0007] Problems to be solved by the invention

[0008] The light from the headlights can irritate the vision of drivers of vehicles ahead and oncoming vehicles, sometimes causing glare that makes it difficult to see objects. Glare is a sensation caused by inappropriate brightness distribution or extreme brightness contrast within the field of vision, which is accompanied by discomfort and reduced observation ability (JIS Z9110). In addition, due to the light emitted by the headlights, the driver of the moving vehicle may also experience glare due to reflected light.

[0009] An object of one embodiment of the present invention is to provide a light emitting device, a headlamp, and a vehicle including the same that can reduce glare and improve durability.

[0010] Solution to the problem

[0011] The first embodiment is a light-emitting device comprising: a light-emitting element having a light emission peak wavelength in a range of not less than 400 nm and not more than 490 nm and a wavelength conversion member, wherein the wavelength conversion member includes a first phosphor having a light emission peak wavelength in a range of not less than 480 nm and less than 580 nm and a second phosphor having a light emission peak wavelength in a range of not less than 580 nm and not more than 680 nm and having a composition different from that of the first phosphor, wherein the light-emitting device emits light having a first brightness ratio Ls / L of not more than 0.9 derived from the following formula (1), wherein the first brightness ratio Ls / L is not more than 0.9. The ratio Ls / L is the ratio of the first effective radiation brightness Ls of the light emitted by the above-mentioned light-emitting device in the range of above 380nm and below 780nm to the brightness L of the light emitted by the above-mentioned light-emitting device in the range of above 380nm and below 780nm, the first effective radiation brightness Ls takes into account the standard relative visibility curve of human photopic vision specified by CIE (International Commission on Illumination) and the spectral sensitivity of human S cones, the brightness L takes into account the above-mentioned standard relative visibility curve of human photopic vision, and the above-mentioned first phosphor includes a rare earth aluminate phosphor having a composition represented by the following formula (1A).

[0012] [Mathematical formula 1]

[0013]

[0014] (In formula (1), S(λ) is the spectral radiation brightness of the light emitted by the light emitting device, V(λ) is the relative visibility curve of the human photopic vision standard specified by CIE, and Gs(λ) is the spectral sensitivity of the human S cone within the wavelength λnm range of 380nm to 550nm.)

[0015] Ln 1 3-e Ce e (Al 1-a Ga a )5O 12 (1A)

[0016] (In formula (1A), Ln 1 is at least one element selected from Y, Gd, Tb and Lu, and a and e satisfy 0≤a≤0.5, 0.019≤e≤0.2. )

[0017] The second mode is a light-emitting device, which comprises a light-emitting element having a light-emitting peak wavelength in the range of greater than 400nm and less than 490nm and a wavelength conversion component, wherein the wavelength conversion component includes a first phosphor having a light-emitting peak wavelength in the range of greater than 480nm and less than 580nm and a second phosphor having a light-emitting peak wavelength in the range of greater than 580nm and less than 680nm and having a composition different from that of the above-mentioned first phosphor, the above-mentioned light-emitting device emits light with a second brightness ratio B / A of less than 0.104 derived from the following formula (2), the second brightness ratio B / A being a ratio of a second effective radiation brightness B of the light emitted by the light-emitting device in the range of greater than 300nm and less than 800nm ​​to a radiation brightness A of the light emitted by the above-mentioned light-emitting device in the range of greater than 300nm and less than 800nm, the second effective radiation brightness B taking into account a scattering intensity curve relative to wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300nm is set to 1, and the above-mentioned first phosphor includes a rare earth aluminate phosphor having a composition represented by the following formula (1A).

[0018] [Mathematical formula 2]

[0019]

[0020] (In formula (2), S(λ) is the spectral radiation brightness of the light emitted by the light emitting device, and Dc(λ) is the scattering intensity curve when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1 in Rayleigh scattering.)

[0021] Ln 1 3-e Ce e (Al 1-a Ga a )5O 12 (1A)

[0022] (In formula (1A), Ln 1 is at least one element selected from Y, Gd, Tb and Lu, and a and e satisfy 0≤a≤0.5, 0.019≤e≤0.2. )

[0023] A third aspect is a headlamp including the above-mentioned light emitting device.

[0024] A fourth aspect is a vehicle including the above-mentioned light emitting device or the above-mentioned headlamp.

[0025] Effects of the Invention

[0026] According to one embodiment of the present invention, a light emitting device, a headlamp, and a vehicle including the same that can reduce glare and improve durability can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1A It is the spectral sensitivity Gs(λ) of the human S cone disclosed in Non-Patent Document 2.

[0028] Figure 1B It is the relative visibility curve V(λ) of the human photopic vision standard specified by CIE disclosed in Non-Patent Document 2.

[0029] Figure 1C The same as V disclosed in Non-Patent Document 2 K (λ): The curve corresponding to K = 1.260 is the spectral visual sensitivity V corresponding to glare K Example of (λ).

[0030] Figure 2 : is a graph showing an intensity curve Dc(λ) of Rayleigh scattering when the scattering intensity at a wavelength of 300 nm is set to 1.

[0031] Figure 3A It is a schematic top view of the light emitting device.

[0032] Figure 3B It is a schematic cross-sectional view of a light emitting device.

[0033] Figure 3C This is an enlarged view of a portion of a schematic cross section of a light emitting device.

[0034] Figure 4 It is a horizontal cross-section of the headlamp.

[0035] Figure 5 It is a front view of the headlamp.

[0036] Figure 6 This is a diagram showing the light emission spectrum of the light emitting device of Example 1 before the reliability evaluation test.

[0037] Figure 7 This is a diagram showing the light emission spectrum of the light emitting device of Example 1 after the reliability evaluation test.

[0038] Figure 8 This is a photograph of the light-transmitting body surface of the light-emitting device of Example 1 after the reliability evaluation test, which was converted into a binary image.

[0039] Fig. 9 This is a photograph of the light-transmitting body surface of the light-emitting device of Comparative Example 1 after the reliability evaluation test, which was binarized.

[0040] Explanation of symbols

[0041] 1: substrate, 10: light emitting element, 12: lighting control unit, 22: outer lens, 24: lamp body, 26: optical filter, 28: screw, 32: substrate, 34: light guiding member, 40: wavelength conversion member, 41: wavelength conversion body, 41a: high concentration layer, 41b: low concentration layer, 42: light transmitting body, 50: semiconductor element, 60: conductive member, 71: first phosphor, 72: second phosphor, 80: adhesive layer, 90: covering member, 100, 101: light emitting device, 200: headlamp. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. Among them, the embodiments shown below illustrate light-emitting devices, headlamps and vehicles equipped therewith for embodying the technical ideas of the present invention, and the present invention is not limited to the light-emitting devices, headlamps and vehicles equipped therewith shown below. In addition, the components shown in the claims are not limited to the components of the embodiments. In particular, for the size, material, shape, relative configuration, etc. of the components described in the embodiments, in the absence of specific descriptions, the scope of the present invention is not limited thereto, and it is only an illustrative example. It should be noted that the relationship between the color name and the chromaticity coordinates, the relationship between the wavelength range of light and the color name of monochromatic light, etc. are based on JIS Z8110. In this specification, when there are multiple substances belonging to each component in the composition, unless otherwise specified, the content of each component in the composition refers to the total amount of the multiple substances present in the composition. In this specification, the half-value full width refers to the wavelength width at which the luminous intensity reaches 50% relative to the luminous intensity at the peak wavelength of light showing the maximum luminous intensity in the luminous spectrum.

[0043] Various light sources such as HID lamps, halogen lamps, and light-emitting devices using LEDs are used in vehicle headlights according to characteristics such as light beams and energy. Depending on the light source, the glare felt and the brightness seen are different. For example, the brightness of the road surface is also affected by the blue light component and the correlated color temperature of the light. Non-patent document 1 discloses an evaluation of the degree to which LED light sources with a correlated color temperature of, for example, 6600K are glaring to both the elderly and the young (Non-patent document 1: Hashimoto Hiroshi et al., "The Effect of Different Color Temperatures of White LEDs on Glare", Japan Automobile Research Institute, Preventive Safety Research Department, October 2006, Automobile Research, Vol. 28, No. 10, p569~p572). Depending on the reduction of retinal illumination in the human body and the deterioration of rod cells, the glare that makes people feel uncomfortable is different, and the degree of glare sometimes varies with the age of the person. Among the cone cells, which are photoreceptor cells present in the human retina, the S cones produce a photoreaction to short-wavelength light. The S cones have a peak wavelength of sensitivity around 440nm. Non-patent document 2 discloses the following formula (3) of a new spectral visual sensitivity VK(λ) corresponding to glare, which takes into account the spectral sensitivity Gs(λ) of the human S cone at wavelength λ in the standard relative visibility curve V(λ) of human photopic vision used in the side-light system of the CIE1931 colorimetric system (Non-patent document 2: Masaji Kobayashi et al., "Research on the Effect of Spectral Distribution of Headlight Sources on Discomfort Glare", Preprint of the Academic Lectures of the Automotive Technology Society, No. 5-10, p9-p14). In this specification, spectral radiation brightness and spectral distribution have the same meaning.

[0044] [Mathematical formula 3]

[0045]

[0046] Figure 1A It is the spectral sensitivity Gs(λ) of the human S cone disclosed in Non-Patent Document 2. Figure 1A , the numerical value of the spectral sensitivity Gs(λ) of the human S cone can be derived. The spectral sensitivity Gs(λ) of the human S cone has a peak spectral sensitivity in the range of 380 nm to 550 nm. Figure 1B It is the relative visibility curve V(λ) of the human photopic vision standard specified by CIE disclosed in Non-Patent Document 2. Figure 1A to Figure 1C The relative values ​​shown are values ​​where the peak of the relative visibility curve V(λ) of the human photopic vision standard specified by CIE is set to 1. Figure 1B , the numerical value of the relative visibility curve V(λ) of the human bright vision standard specified by CIE can be derived. Figure 1C The same as V disclosed in Non-Patent Document 2 K(λ): The curve corresponding to K = 1.260 is the relative visibility curve of the standard photopic vision of people specified by CIE and the spectral visual sensitivity V corresponding to glare taking into account the spectral sensitivity of the human S cone K K is a coefficient that determines the proportion of the contribution of the spectral sensitivity Gs(λ) of the human S cone. The coefficient K in the case of a halogen bulb is 1.260.

[0047] The brightness L of the light emitted by the light emitting device can be derived from the following formula (4). The brightness L of the light emitted by the light emitting device is the integral value of the spectral radiation brightness S(λ) of the light emitting device in the range of 380 nm to 780 nm and the relative visibility curve V(λ) of the human photopic vision standard specified by CIE.

[0048] [Formula 4]

[0049]

[0050] The first effective radiation brightness Ls of the light emitted by the light emitting device can be derived from the following formula (5). The first effective radiation brightness Ls of the light emitted by the light emitting device is the product of the spectral radiation brightness S(λ) of the light emitting device in the range of 380 nm to 780 nm and the spectral visual sensitivity V of a person corresponding to glare expressed by the above formula (3). K The integrated value of (λ) (=K·Gs(λ)+V(λ)) is divided by 2.3 (the coefficient K (=1.260) when using a halogen bulb). V is derived from the above formula (3) K (λ) peak top)

[0051] [Mathematical formula 5]

[0052]

[0053] The first brightness ratio Ls / L of the light emitted by the light emitting device is a ratio of the first effective radiant brightness Ls of the light emitted by the light emitting device taking into account the relative visibility curve of the standard photopic vision of a person specified by CIE and the spectral sensitivity of the human S cone to the brightness L of the light emitted by the light emitting device taking into account the relative visibility curve of the standard photopic vision of a person specified by CIE. The first brightness ratio Ls / L indicates the degree of reduction of the glare of the light emitted by the light emitting device.

[0054] The light-emitting device of the first embodiment includes a light-emitting element having a light emission peak wavelength in the range of 400 nm to 490 nm, a first phosphor having a light emission peak wavelength in the range of 480 nm to less than 580 nm, and a second phosphor having a light emission peak wavelength in the range of 580 nm to 680 nm and having a composition different from that of the first phosphor. The light-emitting device emits light having a first brightness ratio Ls / L of 0.9 or less derived from the following formula (1).

[0055] [Mathematical formula 6]

[0056]

[0057] (In formula (1), S(λ) is the spectral radiation brightness of the light emitted by the light emitting device, V(λ) is the relative visibility curve of the human photopic vision standard specified by CIE, and Gs(λ) is the spectral sensitivity of the human S cone within the wavelength λnm range of 380nm to 550nm.)

[0058] When the first brightness ratio Ls / L of the light emitted by the light-emitting device is 0.9 or less, light with reduced glare can be emitted from the light-emitting device. If the first brightness ratio Ls / L of the light emitted by the light-emitting device is greater than 0.9, it is close to the brightness L of the light emitted by the light-emitting device without considering the spectral sensitivity of the human S cone, and the glare cannot be reduced. In order to reduce uncomfortable glare, the first brightness ratio Ls / L of the light emitted by the light-emitting device is preferably 0.85 or less, more preferably 0.83 or less, further preferably 0.80 or less, and can be 0.7 or less. For the light emitted by the light-emitting device, considering the spectral sensitivity of the human S cone, the first brightness ratio Ls / L can be 0.1 or more, 0.2 or more, preferably 0.3 or more, further preferably 0.4 or more, and further preferably 0.5 or more.

[0059] The light emitting device that emits light having a first brightness ratio Ls / L of 0.9 or less preferably emits light having a second brightness ratio A / B described below of 0.104 or less. The light emitting device that emits light having a first brightness ratio Ls / L of 0.9 or less and a second brightness ratio A / B described below of 0.104 or less can reduce glare and make the light reach far away. The light emitting device of the first embodiment that can reduce glare and make the light reach far away can be used in a headlamp and a vehicle equipped with the headlamp. The headlamp using the light emitting device of the first embodiment and the vehicle equipped with the headlamp can reduce glare of light emitted by the headlamp and the vehicle and make the light reach far away.

[0060] The first phosphor of the light-emitting device of the first embodiment includes a rare earth aluminate phosphor having a composition represented by the following formula (1A).

[0061] Ln 13-e Ce e (Al 1-a Ga a )5O 12 (1A)

[0062] (In formula (1A), Ln 1 is at least one element selected from Y, Gd, Tb and Lu, and a and e satisfy 0≤a≤0.5, 0.019≤e≤0.2. )

[0063] In the rare earth aluminate phosphor represented by the above formula (1A), the variable e representing the molar ratio of Ce as an activation element in the composition is as high as 0.019 or more and 0.2 or less (0.019≤e≤0.2), so the content of the first phosphor contained in the light-emitting device can be reduced, and the light-emitting device can emit light of a desired color tone even when the content of the first phosphor is small. In addition, in the light-emitting device, the variable e representing the molar ratio of Ce as an activation element in the composition of the rare earth aluminate phosphor represented by the above formula (1A) is as high as 0.019 or more and 0.2 or less (0.019≤e≤0.2), so the content of the first phosphor contained in the light-emitting device can be reduced, the heat emitted by the phosphor can be reduced, the deterioration of the light-emitting device such as cracks and fissures caused by heat can be suppressed, and the durability of the light-emitting device can be improved.

[0064] In the above formula (1A), the variable e representing the molar ratio of Ce as an activating element may be within the range of 0.019 to 0.118 (0.019≤e≤0.118), or within the range of 0.019 to 0.115 (0.019≤e≤0.115). In the above formula (1A), the variable a representing the molar ratio of Ga as the product of the variable a and 5 may be within the range of 0 to 0.45 (0≤a≤0.45), or within the range of 0 to 0.40 (0≤a≤0.40).

[0065] The light-emitting device of the second embodiment comprises a light-emitting element having a light emission peak wavelength in the range of 440 nm to 490 nm, a first phosphor having a light emission peak wavelength in the range of 480 nm to less than 580 nm, and a second phosphor having a light emission peak wavelength in the range of 580 nm to 680 nm and having a composition different from that of the first phosphor. The light-emitting device emits light having a second brightness ratio B / A of 0.104 or less derived from the following formula (2), wherein the second brightness ratio B / A is a ratio of a second effective radiant brightness B of light emitted by the light-emitting device in the range of 300 nm to 800 nm to a radiant brightness A of light emitted by the light-emitting device in the range of 300 nm to 800 nm, wherein the second effective radiant brightness B takes into account a scattering intensity curve relative to wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1.

[0066] [Formula 7]

[0067]

[0068] (In formula (2), S(λ) is the spectral radiation brightness of the light emitted by the light emitting device, and Dc(λ) is a scattering intensity curve relative to wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1 in Rayleigh scattering.)

[0069] The scattering caused by the interaction between light and particles can be determined by the relative relationship between the wavelength λ of the light and the size D of the particles. The size D of the particles contained in the air is much smaller than the wavelength λ of the light. Rayleigh scattering is the scattering of light caused by particles with a size smaller than the wavelength of light. In the air, the shorter the wavelength, the easier it is for light to scatter. If the scattering of light is suppressed, the light can reach far away. A light-emitting device that can make light reach far away can be suitably used in a headlamp for a high beam mode that illuminates a far distance ahead of about 100m, for example. The light-emitting device of the second embodiment can suppress scattering and make light reach far away. In addition, a headlamp using the light-emitting device of the second embodiment and a vehicle equipped with the headlamp can also make light reach far away.

[0070] The radiant brightness A of the light emitted by the light emitting device can be derived from the following formula (6): The radiant brightness A of the light emitted by the light emitting device is the integrated value of the spectral radiant brightness S(λ) of the light emitting device in the range of 300 nm to 800 nm.

[0071] [Mathematical formula 8]

[0072]

[0073] Figure 2A scattering intensity curve Dc(λ) with respect to wavelength is shown when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1.

[0074] The second effective radiation brightness B of the light emitted by the light emitting device can be derived from the following formula (7). The second effective radiation brightness B of the light emitted by the light emitting device is the integral value of the above scattering intensity curve Dc(λ) within the range of 300nm to 800nm ​​and the spectral radiation brightness S(λ) of the above light emitting device.

[0075] [Mathematical formula 9]

[0076]

[0077] The second brightness ratio B / A of the light emitted by the light emitting device is a ratio of the second effective radiant brightness B of the light emitted by the light emitting device in the range of 300 nm to 800 nm, taking into account the scattering intensity curve relative to the wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1, to the radiant brightness A of the light emitted by the light emitting device in the range of 300 nm to 800 nm. The second brightness ratio B / A indicates the degree of scattering of the light emitted by the light emitting device.

[0078] When the second brightness ratio B / A of the light emitted by the light emitting device is 0.104 or less, scattering is suppressed, and light that reaches a relatively far distance can be emitted from the light emitting device. When the second brightness ratio B / A of the light emitted by the light emitting device exceeds 0.104, it is close to the radiation brightness A of the light emitted by the light emitting device without considering Rayleigh scattering. In order to suppress scattering and emit light that reaches a relatively far distance, the second brightness ratio B / A of the light emitted by the light emitting device is preferably 0.102 or less, more preferably 0.100 or less, further preferably 0.099 or less, further preferably 0.098 or less, particularly preferably 0.090 or less, and further particularly preferably 0.085 or less. In order to suppress scattering of light, the second brightness ratio B / A of the light emitted by the light emitting device is 0.104 or less. Although the second brightness ratio B / A of the light emitted by the light emitting device is preferably a small value, when the second brightness ratio B / A of the light emitted by the light emitting device is too small, the spectral radiation brightness decreases, and sometimes it is difficult to make the light reach a relatively far distance. Regarding the light emission of the light emitting device, taking into account Rayleigh scattering, the second brightness ratio B / A may be 0.01 or more, 0.02 or more, preferably 0.03 or more, more preferably 0.04 or more, and even more preferably 0.05 or more.

[0079] The light emitting device that emits light with a second brightness ratio B / A of 0.104 or less preferably emits light with the first brightness ratio Ls / L of 0.9 or less. The light emitting device that emits light with a second brightness ratio A / B of 0.104 or less and a first brightness ratio Ls / L of 0.9 or less can make the light reach farther and can also reduce glare.

[0080] The first phosphor of the light-emitting device of the second embodiment includes a rare earth aluminate phosphor having a composition represented by the above formula (1A). In the above formula (1A), the variable e representing the molar ratio of Ce as an activation element may be within a range of 0.019 to 0.118 (0.019≤e≤0.118), or within a range of 0.019 to 0.115 (0.019≤e≤0.115). For the rare earth aluminate phosphor represented by the above formula (1A), since the variable e representing the molar ratio of Ce as an activation element in the composition is as much as 0.019 to 0.2 (0.019≤e≤0.2), the content of the first phosphor included in the light-emitting device can be reduced, and the light-emitting device can emit light of a desired color tone even when the content of the first phosphor is small. In addition, for the light-emitting device, since the variable e representing the molar ratio of Ce as an activating element in the composition of the rare earth aluminate phosphor represented by the above formula (1A) is large, the content of the first phosphor contained in the light-emitting device can be reduced, the heat emitted by the phosphor can be reduced, the degradation of the light-emitting device caused by heat can be suppressed, and the durability of the light-emitting device can be improved.

[0081] Hereinafter, a light emitting device that emits light having a first brightness ratio Ls / L of 0.9 or less and / or a light emitting device that emits light having a second brightness ratio B / A of 0.104 or less will be described. The light emitting device that emits light having a first brightness ratio Ls / L of 0.9 or less and the light emitting device that emits light having a second brightness ratio B / A of 0.104 or less preferably have correlated color temperatures in the same range, and may be light emitting devices of the same type using the same components.

[0082] The light emitting device preferably emits light having a correlated color temperature of 1800 K or more and 5000 K or less, and more preferably emits light having a correlated color temperature of 2000 K or more and 5000 K or less. For example, when the correlated color temperature of light emitted from the light emitting device provided in the headlight is low, it is possible to reduce glare felt by the driver of the vehicle ahead, the oncoming vehicle, or the driving vehicle itself.

[0083] Light-emitting components

[0084] The light-emitting element has a peak emission wavelength in the range of 400 nm to 490 nm. The peak emission wavelength of the light-emitting element is preferably in the range of 420 nm to 480 nm, and can further be in the range of 440 nm to 460 nm. Since at least a part of the light emitted by the light-emitting element can be used as excitation light for the first phosphor and the second phosphor, it is preferred to have a peak emission wavelength that is easy to excite these phosphors. The half-value full width of the emission spectrum of the light-emitting element is preferably less than 30 nm, more preferably less than 25 nm, and further preferably less than 20 nm. For example, the light-emitting element preferably uses a semiconductor light-emitting element that utilizes a nitride semiconductor. Thus, a stable light-emitting device with high efficiency, high linearity of output relative to input, and resistance to mechanical shock can be obtained.

[0085] First phosphor

[0086] The first phosphor is excited by the light of the light-emitting element having a peak wavelength in the range of 400 nm to 490 nm to emit light having a peak wavelength in the range of 480 nm to less than 580 nm. The full width at half maximum of the light emission spectrum of the first phosphor is preferably in the range of 90 nm to 125 nm, and may be in the range of 100 nm to 124 nm, or in the range of 110 nm to 123 nm. When the first phosphor has a peak wavelength in the range of 480 nm to less than 580 nm, the excitation light from the light-emitting element is wavelength-converted, and a mixed light of the light from the light-emitting element and the light after the wavelength conversion by the first phosphor and the second phosphor is emitted from the light-emitting device.

[0087] The first phosphor preferably includes a rare earth aluminate phosphor having a composition represented by the above formula (1A) and includes at least one selected from first nitride phosphors having a composition represented by the following formula (1B).

[0088] La w Ln 2 x Ce z Si6N y (1B)

[0089] (In formula (1B), Ln 2 It must contain at least one selected from Y and Gd, and optionally contains at least one selected from Sc and Lu, and the Ln contained in 1 mol is 2 When the element is set to 100 mol%, Ln 2The total amount of Y and Gd contained in is 90 mol% or more, and w, x, y and z satisfy 1.2≤w≤2.2, 0.5≤x≤1.2, 10≤y≤12, 0.5≤z≤1.2, 1.80<w+x<2.40, 2.9≤w+x+z≤3.1. )

[0090] The first phosphor may include at least one phosphor selected from an alkaline earth metal aluminate phosphor and an alkaline earth metal halosilicate phosphor. The alkaline earth metal aluminate phosphor is, for example, a phosphor containing at least strontium and activated by europium, and has a composition represented by the following formula (1C). In addition, the alkaline earth metal halosilicate is, for example, a phosphor containing at least calcium and chlorine and activated by europium, and has a composition represented by the following formula (1D).

[0091] S4A 14 O 25 :Eu(1C)

[0092] (Ca,Sr,Ba)8MgSi4O 16 (F,Cl,Br)2:Eu(1D)

[0093] In formula (1C), a part of Sr may be substituted with at least one element selected from the group consisting of Mg, Ca, Ba and Zn.

[0094] The alkaline earth metal aluminate phosphor having a composition represented by formula (1C) and the alkaline earth metal halosilicate phosphor having a composition represented by formula (1D) have a light emission peak wavelength in the range of greater than 480 nm and less than 520 nm, preferably in the range of greater than 485 nm and less than 515 nm.

[0095] The full width at half maximum of the emission spectrum of the alkaline earth metal aluminate phosphor having a composition represented by formula (1C) and the alkaline earth metal halosilicate phosphor having a composition represented by formula (1D) is, for example, greater than 30 nm, preferably greater than 40 nm, more preferably greater than 50 nm, and, for example, less than 80 nm, preferably less than 70 nm.

[0096] In the present specification, in the formula representing the composition of the phosphor, the molar ratio of each element in the composition of 1 mole of the parent crystal and the phosphor is indicated before the colon (:), and the activating element is indicated after the colon (:). In the present specification, in the formula representing the composition of the phosphor, a plurality of elements recorded by separating them with a comma (,) means that at least one element among the plurality of elements is included in the composition, and two or more elements selected from the plurality of elements may be included in combination.

[0097] The first phosphor may include at least one phosphor selected from the group consisting of a β-sialon phosphor, a first sulfide phosphor, a scandium-based phosphor, an alkaline earth metal silicate phosphor, and a lanthanide silicon nitride phosphor. The β-sialon phosphor, for example, has a composition represented by the following formula (1E). The first sulfide phosphor, for example, has a composition represented by the following formula (1F). The scandium-based phosphor, for example, has a composition represented by the following formula (1G). The alkaline earth metal silicate phosphor, for example, has a composition represented by the following formula (1H) or a composition represented by the following formula (1J). The lanthanide silicon nitride phosphor, for example, has a composition represented by the following formula (1K).

[0098] Si 6-g Al g O g N 8-g :Eu(0<g≤4.2)(1E)

[0099] (Sr,M 3 )Ga2S4:Eu(1F)

[0100] (In formula (1F), M 3 is at least one element selected from Be, Mg, Ca, Ba and Zn. )

[0101] (Ca,Sr)Sc2O4:Ce(1G)

[0102] (Ca,Sr)3(Sc,Mg)2Si3O 12 :Ce(1H)

[0103] (Ca,Sr,Ba)2SiO4:Eu(1J)

[0104] (La,Y,Gd,Lu)3Si6N 11 :Ce(1K)

[0105] The β-sialon phosphor, the first sulfide phosphor, the scandium-based phosphor, the alkaline earth metal silicate phosphor, and the lanthanide silicon nitride phosphor each have a light emission peak wavelength in the range of 520 nm to less than 580 nm, preferably in the range of 525 nm to 565 nm. The full width at half maximum of the light emission spectrum of the β-sialon phosphor, the first sulfide phosphor, the scandium-based phosphor, the alkaline earth metal silicate phosphor, and the lanthanide silicon nitride phosphor is, for example, 20 nm or more, preferably 30 nm or more, and, for example, 120 nm or less, preferably 115 nm or less.

[0106] The first phosphor may include a rare earth aluminate phosphor having a composition represented by the above formula (1A), including at least one phosphor selected from the following: a first nitride phosphor having a composition represented by the above formula (1B), an alkaline earth metal aluminate phosphor having a composition represented by the above formula (1C), an alkaline earth metal halosilicate phosphor having a composition represented by the above formula (1D), a β-sialon phosphor having a composition represented by the above formula (1E), a first sulfide phosphor having a composition represented by the above formula (1F), a scandium-based phosphor having a composition represented by the above formula (1G), an alkaline earth metal silicate phosphor having a composition represented by the above formula (1H), an alkaline earth metal silicate phosphor having a composition represented by the above formula (1J), and a lanthanide silicon nitride phosphor having a composition represented by the above formula (1K). The first phosphor may include at least one phosphor having a composition represented by the above formula (1A) alone, or may include two or more of them.

[0107] Second phosphor

[0108] The second phosphor is excited by the light emission of a light-emitting element having a peak emission wavelength in the range of 400 nm to 490 nm, emits light having a peak emission wavelength in the range of 580 nm to 680 nm, and has a composition different from that of the first phosphor. The half-value width of the emission spectrum of the second phosphor is preferably in the range of 3 nm to 15 nm. As such a second phosphor, for example, it is preferred to include a fluoride phosphor having a composition represented by the following formula (2C) or a fluoride phosphor having a composition represented by the following formula (2C'). Alternatively, it is preferred that the half-value width in the emission spectrum is in the range of 60 nm to 125 nm. As such a second phosphor, for example, it is preferred to include a second nitride phosphor having a composition represented by the following formula (2A), a third nitride phosphor having a composition represented by the following formula (2B), or an α-sialon phosphor having a composition represented by the following formula (2G). The excitation light from the light-emitting element is wavelength-converted by the second phosphor, and mixed light of the light from the light-emitting element and the light after the wavelength conversion by the first phosphor and the second phosphor is emitted from the light-emitting device.

[0109] The second phosphor preferably includes at least one selected from the following: a second nitride phosphor having a composition represented by the following formula (2A), a third nitride phosphor having a composition represented by the following formula (2B), a fluoride phosphor having a composition represented by the following formula (2C), a fluoride phosphor having a composition represented by the following formula (2C') different from the composition of the following formula (2C), and an α-sialon phosphor having a composition represented by the following formula (2G). In this specification, the second nitride phosphor having a composition represented by the following formula (2A) is sometimes represented as a BSESN phosphor, and the third nitride phosphor having a composition represented by the following formula (2B) is sometimes represented as a SCASN phosphor.

[0110] M 1 2Si5N8:Eu(2A)

[0111] (In formula (2A), M 1 Contains at least one alkaline earth metal element selected from Ca, Sr and Ba.

[0112] Sr q Ca s Al t Si u N v :Eu(2B)

[0113] (In formula (2B), q, s, t, u, and v satisfy 0≤q<1, 0<s≤1, q+s≤1, 0.9≤t≤1.1, 0.9≤u≤1.1, and 2.5≤v≤3.5, respectively.)

[0114] A c [M 2 1-b Mn 4＋ b F d ](2C)

[0115] (In formula (2C), A comprises a ＋ , Li ＋ 、Na ＋ , Rb ＋ , Cs ＋ and NH4 ＋ At least one of the following, preferably K ＋ . M 2 Contains at least one element selected from Group 4 elements and Group 14 elements, and preferably Si and Ge. B satisfies 0<b<0.2, and c satisfies [M 2 1-b Mn 4＋ b F d ]The absolute value of the charge of the ion, d satisfies 5<d<7. )

[0116] A' c’ [M 2 ' 1-b’ Mn 4+ b’ F d’ ](2C')

[0117] (In formula (2C'), A' comprises a ＋ , Li ＋ 、Na ＋ , Rb ＋ , Cs ＋ and NH4 ＋ At least one of the following, preferably K ＋ . M 2 ' contains at least one element selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, preferably Si and Al. b' satisfies 0<b'<0.2, c' is [M 2 ' 1-b’ Mn 4＋ b’ F d’ ]The absolute value of the charge of the ion, d' satisfies 5<d'<7. )

[0118] M 8 v3 Si 12-(w3＋x3) Al w3＋x3 O x3 N 16-x3 :Eu(2G)

[0119] (In formula (2G), M 8 Contains at least one element selected from Li, Mg, Ca, Sr, Y and lanthanide elements (except La and Ce), and v3, w3 and x3 satisfy 0<v3≤2.0, 2.0≤w3≤6.0, 0≤x3≤1.0 respectively. )

[0120] The second phosphor may include at least one phosphor selected from a fluorogermanate phosphor, a fourth nitride phosphor, and a second sulfide phosphor. The fluorogermanate phosphor, for example, has a composition represented by the following formula (2D). The fourth nitride phosphor, for example, has a composition represented by the following formula (2E). The second sulfide phosphor, for example, has a composition represented by the following formula (2F).

[0121] (ij) MgO·(j / 2)Sc2O3·kMgF2·mCaF2·(1-n)GeO2·(n / 2)M 4 2O3:Mn(2D)

[0122] (In formula (2D), M 4is at least one selected from Al, Ga and In. i, j, k, m, n and z respectively satisfy 2≤i≤4, 0≤j<0.5, 0<k<1.5, 0≤m<1.5, 0≤n<0.5. )

[0123] M 5 v2 M 6 w2 Al 3-y2 Si y2 N z2 :M 7 (2E)

[0124] (In formula (2E), M 5 is at least one element selected from Ca, Sr, Ba and Mg, M 6 is at least one element selected from Li, Na and K, M 7 is at least one element selected from Eu, Ce, Tb and Mn, and v2, w2, y2 and z2 satisfy 0.80≤v2≤1.05, 0.80≤w2≤1.05, 0≤y2≤0.5, 3.0≤z2≤5.0 respectively. )

[0125] (Ca,Sr)S:Eu(2F)

[0126] The fluorogermanate phosphor having the composition represented by formula (2D) may have a composition represented by the following formula (2d).

[0127] 3.5MgO·0.5MgF2·GeO2:Mn(2d)

[0128] The fourth nitride phosphor having a composition represented by formula (2E) may have a composition represented by the following formula (2e).

[0129] M 5 v2 M 6 w2 M 7 x2 Al 3-y2 Si y2 N z2 (2e)

[0130] (In formula (2e), M 5 、M 6 and M 7 Respectively with M in formula (2E) 5 、M 6 and M 7has the same meaning, and is at least one element selected from Ce, Tb and Mn, v2, w2, y2 and z2 have the same meanings as v2, w2, y2 and z2 in formula (2E), respectively, and x2 satisfies 0.001<x2≤0.1.)

[0131] The fluorogermanate phosphor, the fourth nitride phosphor, and the second sulfide phosphor each have a luminescence peak wavelength in the range of 580 nm to 680 nm, preferably in the range of 600 nm to 630 nm. The fluorogermanate phosphor, the fourth nitride phosphor, and the second sulfide phosphor each have a luminescence peak full width at half maximum in the luminescence spectrum of, for example, 5 nm to 100 nm, preferably 6 nm to 90 nm.

[0132] The second phosphor preferably includes at least one selected from the following: a second nitride phosphor having a composition represented by the above formula (2A), a third nitride phosphor having a composition represented by the above formula (2B), a fluoride phosphor having a composition represented by the above formula (2C), a fluoride phosphor represented by the above formula (2C'), a fluorogermanate phosphor having a composition represented by the above formula (2D), a fourth nitride phosphor having a composition represented by the above formula (2E), a second sulfide phosphor having a composition represented by the above formula (2F), and an α-sialon phosphor having a composition represented by the above formula (2G). The second phosphor may include at least one phosphor alone, or may include two or more phosphors.

[0133] The second phosphor further preferably includes at least one selected from the following: a second nitride phosphor (BSESN phosphor) having a composition represented by the above formula (2A), a third nitride phosphor (SCASN phosphor) having a composition represented by the above formula (2B), and an α-sialon phosphor having a composition represented by the above formula (2G). At least one second phosphor selected from the BSESN phosphor, the SCASN phosphor, and the α-sialon phosphor has good temperature characteristics, and the change in luminous energy caused by the change in temperature is small. For example, in a light-emitting device having a wavelength conversion member, the wavelength conversion member includes a rare earth aluminate phosphor having a composition represented by the above formula (1A) as a first phosphor, and includes at least one selected from a BSESN phosphor, a SCASN phosphor, and an α-sialon phosphor as a second phosphor. Since the temperature characteristics of the first phosphor and the second phosphor are good, even when used in a cold environment such as -40°C or a high temperature environment exceeding 100°C, the first brightness ratio Ls / L is maintained at a state of 0.9 or less, and the rate of change of the first brightness ratio Ls / L is small, and it is not easily affected by the ambient temperature of the use environment, and the light-emitting device can emit light with reduced glare. In a state where the first brightness ratio Ls / L is maintained at 0.9 or less, the temperature characteristics of the light-emitting device that can emit light with a small rate of change of the first brightness ratio Ls / L even when the temperature of the use environment of the light-emitting device changes are sometimes good.

[0134] In a light-emitting device having a wavelength conversion member, the wavelength conversion member includes a rare earth aluminate phosphor having a composition represented by the above formula (1A) as a first phosphor, and includes at least one selected from a BSESN phosphor, a SCASN phosphor, and an α-sialon phosphor as a second phosphor. Since the temperature characteristics of the first phosphor and the second phosphor are good, the light is not easily affected by the ambient temperature of the use environment, and the second brightness ratio B / A is maintained at 0.104 or less. The rate of change of the second brightness ratio B / A is small, and the light-emitting device can emit light that is not easily affected by the ambient temperature of the use environment, suppresses scattering, and can reach a long distance. When the second brightness ratio B / A is maintained at 0.104 or less, the temperature characteristics of the light-emitting device that can emit light with a small rate of change of the second brightness ratio B / A even when the temperature of the use environment of the light-emitting device changes are sometimes good.

[0135] For the phosphor including the first phosphor and the second phosphor, the average particle size measured by the Fisher Sub-Sieve Sizer (hereinafter also referred to as "FSSS") method is preferably within the range of 5 μm to 40 μm, more preferably within the range of 6 μm to 35 μm, and further preferably within the range of 7 μm to 30 μm. When the average particle size of the phosphor is within the range of 5 μm to 40 μm, the phosphor can be used to efficiently absorb light emitted from the excitation light source and perform wavelength conversion, and light with reduced glare or light that suppresses light scattering and reaches a farther distance can be emitted from the light emitting device.

[0136] For the rare earth aluminate phosphor having a composition represented by the above formula (1A), the average particle size measured by the FSSS method is preferably within a range of 15 μm or more and 40 μm, more preferably within a range of 16 μm or more and 35 μm or less, and further preferably within a range of 17 μm or more and 30 μm or less. When the rare earth aluminate phosphor having a composition represented by the above formula (1A) is a phosphor having a relatively large average particle size within a range of 15 μm or more and 40 μm or less as measured by the FSSS method, the content of the first phosphor contained in the light-emitting device can be reduced, and the light-emitting device can emit light of a desired hue even when the content of the first phosphor is small.

[0137] Light-emitting device

[0138] A method of a light emitting device will be described. Figure 3A An example of a light emitting device is shown, and is a schematic top view of a light emitting device 101 . Figure 3B yes Figure 3ASchematic cross-sectional view of the light emitting device 101 taken along line III-III' shown in FIG. The light emitting device 101 includes a light emitting element 10 having a peak emission wavelength in the range of 400 nm to 490 nm, and a wavelength conversion member 40, wherein the wavelength conversion member 40 includes: a wavelength conversion member 41 including a first phosphor 71 and a second phosphor 72 that emit light when excited by light from the light emitting element 10, and a light-transmitting member 42 on which the wavelength conversion member 41 is disposed. The light emitting element 10 is flip-chip mounted on the substrate 1 via a bump as a conductive member 60. The wavelength conversion member 31 of the wavelength conversion member 40 is disposed on the light emitting surface of the light emitting element 10 via an adhesive layer 80. The side surfaces of the light emitting element 10 and the wavelength conversion member 40 are covered by a covering member 90 that reflects light. The wavelength converter 41 includes a first phosphor 71 which is excited by light from the light emitting element 10 and has a peak emission wavelength in the range of 480 nm to less than 580 nm, and a second phosphor 72 which has a peak emission wavelength in the range of 580 nm to 680 nm and has a composition different from that of the first phosphor 71. The light emitting element 10 receives power supply from the outside of the light emitting device 101 via wiring and a conductive member 60 formed on the substrate 1, and can make the light emitting device 101 emit light. The light emitting device 101 may include a semiconductor element 50 such as a protective element for preventing the light emitting element 10 from being damaged by application of an excessive voltage. The covering member 90 is provided, for example, to cover the semiconductor element 50. The following describes each member used in the light emitting device. It should be noted that for details, reference can also be made to the disclosure of, for example, Japanese Patent Application Laid-Open No. 2014-112635.

[0139] Wavelength conversion component

[0140] The wavelength conversion component may be a wavelength conversion body including a phosphor and a translucent material as the wavelength conversion component, or may be a wavelength conversion component further including a translucent body configured with the wavelength conversion body. The wavelength conversion body preferably includes a first phosphor and a second phosphor and a translucent material. The wavelength conversion body may be formed into a plate, a sheet or a layer. The wavelength conversion component may include a wavelength conversion body in other forms other than a plate, a sheet or a layer. Preferably, the wavelength conversion component includes a wavelength conversion body including a first phosphor and a second phosphor, and a translucent material, and the total amount of the first phosphor and the second phosphor of the wavelength conversion body is within the range of 50 parts by mass or more and 500 parts by mass or less relative to 100 parts by mass of the translucent material. When the total amount of the first phosphor and the second phosphor contained in the wavelength converter is within the range of 50 parts by mass or more and 500 parts by mass or less relative to 100 parts by mass of the translucent material, the total amount of the first phosphor and the second phosphor is less relative to the translucent material, which can reduce the heat when the phosphor absorbs the excitation light and emits light, can suppress the degradation of the light-emitting device caused by heat, and can improve the durability of the light-emitting device. The total amount of the first phosphor and the second phosphor contained in the wavelength converter can be within the range of 80 parts by mass or more and 400 parts by mass or less, can be within the range of 90 parts by mass or more and 350 parts by mass or less, can be within the range of 100 parts by mass or more and 300 parts by mass or less, and can be within the range of 100 parts by mass or more and 270 parts by mass or less relative to 100 parts by mass of the translucent material. The total amount of the first phosphor and the second phosphor is also referred to as the total amount of phosphors.

[0141] Preferably, the wavelength conversion member includes a wavelength conversion body including a first phosphor and a second phosphor, and a translucent material, and in the thickness direction of the cross section, the wavelength conversion body includes: a high concentration layer having a high filling rate of the first phosphor and the second phosphor and a high concentration of the first phosphor and the second phosphor, and a low concentration layer having a low filling rate of the first phosphor and the second phosphor and a low concentration of the first phosphor and the second phosphor. By providing the wavelength conversion body with a high concentration layer having a high filling rate of the first phosphor and the second phosphor, cracks and cracks are not easily generated in the wavelength conversion body even when the total amount of the phosphor is small relative to the translucent material. For the wavelength conversion body, it is preferred that the high concentration layer is arranged on the light-emitting element side. By arranging the high concentration layer on the light-emitting element side, the wavelength conversion body can dissipate the heat generated by the light-emitting element through the first phosphor and the second phosphor in the wavelength conversion body. For the filling rate of the phosphor, the cross section of the wavelength conversion body or the cross section of the wavelength conversion member can be observed using a scanning electron microscope (SEM), and the filling rate of the phosphor can be measured based on the area ratio of the resin to the phosphor in the cross section. A high-concentration layer with a high filling rate of phosphor refers to a layer in which the area of ​​phosphor is larger than the area of ​​resin in the cross section of the wavelength converter or the cross section of the wavelength conversion member. A low-concentration layer with a low filling rate of phosphor refers to a layer in which the area of ​​phosphor is smaller than the area of ​​resin in the cross section of the wavelength converter or the cross section of the wavelength conversion member. A low-concentration layer may be a layer in which phosphor is substantially absent, there is no area of ​​phosphor, and only the area of ​​resin can be confirmed. In the cross section of the wavelength converter observed by SEM, for the ratio of the thickness of the high-concentration layer to the thickness of the low-concentration layer, when the overall thickness of the wavelength converter is set to 100%, the thickness of the low-concentration layer may be less than 40%, less than 35%, less than 34%, more than 3%, or more than 5%. When the ratio of the thickness of the low-concentration layer is large, the ratio of the thickness of the high-concentration layer is small, and the filling rate of the first phosphor and the second phosphor contained in the high-concentration layer is high, indicating that the density of the high-concentration layer is high. In order to suppress cracks and fissures in the wavelength converter and improve heat dissipation, it is preferred that the filling rate of the first phosphor and the second phosphor in the high concentration layer be high and the density of the first phosphor and the second phosphor be high.

[0142] Figure 3C yes Figure 3B A partial enlarged view of a portion P1 of a schematic cross section of the light emitting device shown. Figure 3C and Figure 3B The scales are different.

[0143] The wavelength converter 41 includes a high concentration layer 41a having a high filling rate of the first phosphor 71 and the second phosphor 72, and a low concentration layer 41b having a low filling rate of the first phosphor 71 and the second phosphor 72, and the high concentration layer 41a is arranged on the light emitting element 10 side. The low concentration layer 41b of the wavelength converter 41 is arranged on the light transmitting body 42 side. The wavelength converter 41 is provided on the light emitting surface of the light emitting element 10 via the adhesive layer 80.

[0144] The headlamp uses a high-output light-emitting device, so a wavelength conversion member with high heat resistance, such as a wavelength conversion member formed by coating a resin composition containing a phosphor on a light-transmitting body formed of highly heat-resistant glass, or a sintered body containing a phosphor and a light-transmitting material, may be used. Regarding the phosphor contained in the wavelength conversion member with high heat resistance, a phosphor that is considered to have higher heat resistance than other phosphors may be used, for example, a phosphor having a Y3Al5O 12 : Ce. For this rare earth aluminate phosphor, the luminous intensity at the long wavelength side of 570nm or more is small, so when used in a headlamp, it usually emits light with a correlated color temperature of around 6000K. Therefore, it is considered that the phosphor contained in the wavelength conversion member is only a phosphor with a color of Y3Al5O 12 In the case of a rare earth aluminate phosphor having a composition represented by Ce, it is difficult to realize a headlamp that emits light with a correlated color temperature of 5000K or less. The light-emitting device of the first embodiment or the light-emitting device of the second embodiment may include one of the first phosphor and the second phosphor as the phosphor included in the sintered body for the wavelength conversion member, or may include two or more of the first phosphor and the second phosphor. As the phosphor included in the sintered body, a phosphor having a composition represented by the above formula (1A) may be included as the first phosphor, and for example, the following phosphors may be included.

[0145] (Ba,Sr,Ca)2Si5N8:Eu

[0146] (La,Y,Gd,Lu)3Si6N 11 :Ce

[0147] (Ca,Sr)AlSiN3:Eu

[0148] In addition, the sintered body used in the wavelength conversion component can be a sintered body in which a phosphor having a composition represented by the above formula (1A) and a second nitride phosphor are contained in one sintered body, or a sintered body in which a sintered body containing a phosphor having a composition represented by the above formula (1A) and a sintered body containing a second nitride phosphor are combined into two layers.

[0149] In addition, as the wavelength converter used in the wavelength conversion member, glass can be used as a light-transmitting material. For example, a wavelength converter containing glass and an α-sialon phosphor having a composition formula M can be used. 8 v3 (Si,Al) 12 (O,N) 16 :Eu(M 8 It is represented by Li, Mg, Ca, Y and lanthanide elements other than La and Ce, and v3 satisfies 0<v3≤2).

[0150] It is considered that by using these as wavelength conversion members, the light emitting device emits light with a correlated color temperature of 5000K or less, and by using the light emitting device, a headlamp capable of reducing glare and a vehicle including the headlamp can be provided.

[0151] Translucent materials

[0152] The light-transmitting material may include at least one selected from resin, glass and inorganic substances. The resin is preferably at least one selected from epoxy resin, silicone resin, phenolic resin and polyimide resin. The inorganic substance may include at least one selected from aluminum oxide and aluminum nitride.

[0153] When the light-transmitting material is a resin, a resin having a Shore A hardness of 30 to 80 is preferred. The light-transmitting material is preferably a silicone resin, preferably a silicone resin having a Shore A hardness of 30 to 80. The Shore A hardness of the silicone resin as the light-transmitting material is more preferably in the range of 40 to 75, and further preferably in the range of 50 to 70. When the light-transmitting material is a resin, the resin expands or contracts due to light and heat. When the light-transmitting material is a silicone resin having a Shore A hardness of 30 to 80, it has excellent toughness and elongation. Therefore, even when the temperature of the ambient atmosphere changes, it will flexibly expand and contract with the temperature change, and cracks and fissures in the wavelength converter are not likely to occur. It can emit light that keeps the first brightness ratio Ls / L below 0.9, and has good temperature characteristics. When the light-transmitting material is a silicone resin with a Shore A hardness of 30 or more and 80 or less, it can flexibly expand and contract with temperature changes, and the wavelength converter is not prone to cracks and fissures, etc., and can emit light that keeps the second brightness ratio B / A at 0.104 or less, and has good temperature characteristics. The Shore A hardness of the resin can be measured using a type A durometer in accordance with JIS K6253.

[0154] For example, when a wavelength converter is formed using a resin with a low Shore A hardness of less than about 30 as a light-transmitting material, the wavelength converter is soft and adhesive. Therefore, when each light-emitting device is singulated from a composite substrate having a plurality of light-emitting elements, it is difficult to cut it, and it is difficult to transport and package it, resulting in poor mass production.

[0155] Therefore, by using a resin having a Shore A hardness of 30 or more and 80 or less as the light-transmitting material, a wavelength converter in which cracks and fissures are unlikely to occur in the wavelength converter or the wavelength conversion member and which has good temperature characteristics can be obtained.

[0156] Translucent

[0157] The wavelength conversion component may include a light-transmitting body. The light-transmitting body may be a plate-shaped body formed 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 such that the mechanical strength is not reduced during the manufacturing process and the thickness is sufficient to support the wavelength conversion body.

[0158] substrate

[0159] The substrate is preferably formed of an insulating material that is difficult for light from the light emitting element and external light to transmit. As the material of the substrate, ceramics such as alumina and aluminum nitride, phenolic resins, epoxy resins, polyimide resins, bismaleimide triazine resins (BT resins), polyphthalamide (PPA) resins and other resins can be cited. Ceramics have high heat resistance and are therefore preferably used as the material of the substrate.

[0160] Adhesive layer

[0161] The light-emitting element and the wavelength conversion member are fixed via an adhesive layer between the light-emitting element and the wavelength conversion member. The adhesive constituting the adhesive layer is preferably formed of a material capable of optically connecting the light-emitting element and the wavelength conversion member. As the material constituting the adhesive layer, it is preferably at least one resin selected from epoxy resin, silicone resin, phenolic resin and polyimide resin.

[0162] Semiconductor components

[0163] Semiconductor elements provided as needed in the light emitting device include, for example, transistors for controlling the light emitting element and protection elements for suppressing the destruction and performance degradation of the light emitting element due to the application of excessive voltage. As a protection element, a Zener diode can be cited.

[0164] Cladding components

[0165] As the material of the covering member, an insulating material is preferably used. More specifically, phenolic resin, epoxy resin, bismaleimide triazine resin (BT resin), polyphthalamide (PPA) resin, silicone resin can be cited. Colorants, phosphors, and fillers can be added to the covering member as needed.

[0166] Conductive components

[0167] As the conductive member, a bump can be used, and as the material of the bump, Au or its alloy can be used. As the other conductive member, eutectic solder (Au—Sn), Pb—Sn, lead-free solder, etc. can be used.

[0168] Method for manufacturing a light emitting device

[0169] An example of a method for manufacturing a light-emitting device is described. It should be noted that for details, reference may also be made to the disclosure of, for example, Japanese Patent Publication No. 2014-112635 or Japanese Patent Publication No. 2017-117912. 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 required, 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.

[0170] Light-emitting element placement process

[0171] The light emitting element is arranged on the substrate. The light emitting element and the semiconductor element are mounted on the substrate, for example, by flip chip.

[0172] Process for forming wavelength conversion member including wavelength converter

[0173] In the step of forming a wavelength conversion member including a wavelength converter, the wavelength converter can be obtained by forming a plate-shaped, sheet-shaped or layer-shaped wavelength converter on one side of a light-transmitting body by a printing method, a bonding method, a compression molding method or an electrodeposition method. For example, a wavelength converter composition including a phosphor and a resin that is a light-transmitting material can be printed on one side of a light-transmitting body by a printing method to form a wavelength conversion member including a wavelength converter.

[0174] Composition for wavelength converter

[0175] The wavelength converter composition constituting the wavelength converter or wavelength converter member includes a translucent material and a first phosphor and a second phosphor, and may include a solvent. When the wavelength converter composition includes a solvent, the viscosity of the wavelength converter composition decreases, and when the wavelength converter composition is cured, even when the total amount of phosphors is less than that of the translucent material, the density of the first phosphor and the second phosphor in the gravity direction increases, and a wavelength converter or wavelength converter member having different filling rates of the first phosphor and the second phosphor in the wavelength converter or wavelength converter member can be manufactured. The wavelength converter or wavelength converter member is less likely to have cracks or fissures in the wavelength converter due to the presence of a portion with a high filling rate of the first phosphor and the second phosphor. By arranging the high-concentration layer side with a high filling rate of the first phosphor and the second phosphor of the wavelength converter on the light-emitting element side, even when a high-output light-emitting element is used, the heat generated by the light-emitting element can be dissipated through the first phosphor and the second phosphor in the wavelength converter, and cracks and fissures in the resin constituting the wavelength converter can be suppressed, and light with a first brightness ratio Ls / L kept at 0.9 or less can be emitted, and the temperature characteristics are good. By arranging the high-concentration layer side with a high filling rate of the first phosphor and the second phosphor of the wavelength converter on the light-emitting element side, even when a high-output light-emitting element is used, the heat generated by the light-emitting element can be dissipated through the first phosphor and the second phosphor in the wavelength converter, and cracks and fissures in the resin constituting the wavelength converter can be suppressed, and light with a second brightness ratio B / A kept at 0.104 or less can be emitted, and the temperature characteristics are good.

[0176] Regarding the solvent, considering the solubility and volatility in the light-transmitting resin, the boiling point under standard pressure (0.101 MPa) is preferably within the range of 150°C to 320°C, more preferably within the range of 170°C to 305°C, further preferably within the range of 180°C to 300°C, and particularly preferably within the range of 190°C to 290°C. By including a solvent having a boiling point within the range of 150°C to 320°C under standard pressure in the wavelength converter composition, when the viscosity of the wavelength converter composition is reduced and the composition is cured, a high-concentration layer having a high filling rate of the phosphors including the first phosphor and the second phosphor in the gravity direction and a low-concentration layer having a low filling rate of the first phosphor and the second phosphor can be formed.

[0177] The viscosity of the wavelength converter composition at 25° C. and 1 rpm measured with an E-type viscometer is preferably in the range of 5 mPa·s to 400 mPa·s, more preferably in the range of 6 mPa·s to 300 mPa·s, and further preferably in the range of 8 mPa·s to 250 mPa·s.

[0178] When the light-transmitting material is a silicone resin, for the composition for wavelength converter, when the total amount of phosphor contained in 100 parts by mass of the light-transmitting material is in the range of 50 parts by mass or more and 500 parts by mass or less, the content of the solvent is preferably in the range of 1 part by mass or more and 50 parts by mass or less, more preferably in the range of 2 parts by mass or more and 40 parts by mass or less, and even more preferably in the range of 3 parts by mass or more and 30 parts by mass or less.

[0179] The solvent is a liquid of an organic compound, a part of which evaporates (volatizes) at room temperature. For example, the residual solvent in the wavelength converter composition can be volatilized by heating at 180°C or above, and the wavelength converter composition can be cured to form a wavelength converter or a wavelength conversion member. Examples of the solvent include hydrocarbon solvents, ketone solvents, alcohol solvents, aldehyde solvents, glycol solvents, ether solvents, ester solvents, glycol ether solvents, glycol ester solvents, etc. Examples of hydrocarbon solvents include hexane, xylene, heptane, decane, dodecane, tridecane, etc. Examples of ketone solvents include acetone, methyl ethyl ketone, etc. Examples of alcohol solvents include methanol, ethanol, isopropanol, etc. Examples of aldehyde solvents include nonanal, decanal, etc. Examples of glycol solvents include triethylene glycol, etc. Examples of ether solvents include diethyl ether, etc. Examples of ester solvents include methyl acetate, ethyl acetate, etc. Examples of glycol ether solvents include propylene glycol monomethyl ether, etc. The glycol ester solvents include ethylene glycol monoethyl ether acetate and the like. The solvent is preferably at least one selected from hexane, xylene, heptane, acetone, ethanol, isopropanol, decane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, nonanal, decanal and triethylene glycol. The solvent is more preferably at least one selected from dodecane, tetradecane, pentadecane, hexadecane and tridecane. The solvent may be used alone or in combination of two or more.

[0180] Wavelength conversion body or wavelength conversion member

[0181] When the composition for wavelength converter contains a solvent, a wavelength converter or wavelength converter member can be formed which is divided into a high concentration layer with a high filling rate of the first phosphor and the second phosphor and a low concentration layer with a low filling rate of the first phosphor and the second phosphor along the gravity direction when the composition for wavelength converter is cured. In this specification, the high concentration layer with a high filling rate of the phosphor and the low concentration layer with a low filling rate of the phosphor can be confirmed in the thickness direction of the cross section of the wavelength converter. As described above, the filling rate of the phosphor can be determined by observing the cross section of the wavelength converter or the cross section of the wavelength converter member with SEM and measuring the filling rate of the phosphor based on the area ratio of the resin to the phosphor in the cross section. The boundary between one layer and other layers may have projections and depressions and not be on a straight line.

[0182] Bonding process of light emitting element and wavelength conversion member

[0183] In the bonding process of the light-emitting element and the wavelength conversion member, the wavelength conversion member is made to face the light-emitting surface of the light-emitting element, and the wavelength conversion member is bonded to the light-emitting element through the bonding layer. In the case where the wavelength conversion member includes a wavelength converter and a light-transmitting body, and the wavelength converter includes a high-concentration layer with a high filling rate of the phosphor and a low-concentration layer with a low filling rate of the phosphor, it is preferred to arrange the high-concentration layer with a high filling rate of the wavelength converter on the light-emitting element side, and bond the wavelength conversion member to the light-emitting element. The thermal conductivity of the phosphor including the first phosphor and the second phosphor is higher than that of the resin. By arranging the high-concentration layer with a high filling rate of the phosphor of the wavelength converter on the light-emitting element side and bonding the wavelength conversion member, heat dissipation becomes good, cracks and fissures of the wavelength converter are less likely to occur, and the temperature characteristics are good.

[0184] Forming process of covering member

[0185] In the process of forming the covering member, the side surfaces of the light emitting element and the wavelength conversion member are covered with the covering member composition. The covering member is used to reflect the light emitted from the light emitting element. When the light emitting device also includes a semiconductor element, it is preferably formed in a manner that the semiconductor element is buried by the covering member. It may include: a process of singulating a composite substrate having a plurality of light emitting elements and semiconductor elements on a substrate into individual light emitting devices.

[0186] For example, when a wavelength converter is formed using a resin with a low Shore A hardness of less than about 30 as a light-transmitting material, since the wavelength converter is soft and adhesive, it is sometimes difficult to cut when a composite substrate having a plurality of light-emitting elements is singulated into individual light-emitting devices, and it is also difficult to transport and package, resulting in poor mass producibility.

[0187] Therefore, by using a resin having a Shore A hardness of 30 or more and 80 or less as the light-transmitting material, a wavelength converter in which cracks and fissures are less likely to occur in the wavelength converter or the wavelength conversion member and which has good temperature characteristics can be obtained.

[0188] headlamp

[0189] The light emitting device can be arranged on a supporting substrate of a light source unit for a headlamp, and used as a headlamp mounted on a vehicle. The light source unit for a headlamp can use, for example, the light source unit disclosed in Japanese Patent Publication No. 2003-317513. The light source unit, for example, includes a supporting substrate for disposing a reflector, a projection lens, and a light emitting device. The light source unit for a headlamp can be controlled to light up by, for example, a vehicle lighting system disclosed in Japanese Patent Publication No. 8-67199. The light emitting device can be used as a light source for a headlamp used for a turn signal lamp disclosed in Japanese Patent Publication No. 2005-123165. Figure 4It is a horizontal cross-section of the headlamp. Figure 5 It is a front view of the headlamp. Figure 4 and Figure 5 The headlamp 200 shown is, for example, installed on the right side in front of the vehicle. The headlamp 200 includes a lamp body 24, an outer lens 22, a plurality of substrates 32, a plurality of light emitting devices 100, an optical filter 26, and a light guide member 34. The lamp body 24 and the outer lens 22 form a lamp chamber of the headlamp 200, and the plurality of substrates 32 and the plurality of light emitting devices 100 are waterproofly held in the lamp chamber. The lamp body 24 is formed, for example, by covering the plurality of substrates 32 and the plurality of light emitting devices 100 with resin from the rear of the vehicle. The optical filter 26 is fixed to the lamp body 24 by a plurality of screws 28. The plurality of light emitting devices 100 are each lit according to the power received from the lighting control unit 12 via the substrate 32.

[0190] A headlamp may include a plurality of first lamp units in which a light emitting device is arranged in a light source unit, as disclosed in Japanese Patent Application Laid-Open No. 2003-317513, for example. Also, a headlamp may include a plurality of reflectors, a plurality of projection lenses, and a second lamp unit in which a plurality of light emitting devices are arranged in a light source unit formed integrally with a plurality of support substrates, as disclosed in Japanese Patent Application Laid-Open No. 2005-141917, for example. The headlamp may include two or more light emitting devices having different first brightness ratios Ls / L. For the two or more light emitting devices having different first brightness ratios Ls / L, one light emitting device may be arranged in one light source unit, respectively. For the two or more light emitting devices having different first brightness ratios Ls / L, two or more light emitting devices may be arranged in one light source unit, respectively. The headlamp may include two or more light emitting devices having different second brightness ratios B / A. For the two or more light emitting devices having different second brightness ratios B / A, one light emitting device may be arranged in one light source unit, respectively. Two or more types of light emitting devices having different second brightness ratios B / A may be arranged in one light source unit.

[0191] The headlamp may include two or more light emitting devices, the first light emitting device emitting light having a first brightness ratio Ls / L of less than 0.9 and the second light emitting device emitting light having a first brightness ratio Ls / L exceeding 0.9.

[0192] The headlamp can have two or more light-emitting devices, including the above-mentioned light-emitting device that emits light with a second brightness ratio B / A of less than 0.104 as the first light-emitting device and the light-emitting device that emits light with a second brightness ratio B / A exceeding 0.104 as the second light-emitting device.

[0193] The second light emitting device may be a light emitting device that emits light having a first brightness ratio Ls / L exceeding 0.9 or a light emitting device that emits light having a second brightness ratio B / A exceeding 0.104. Figure 3A and Figure 3B The first light-emitting device shown is of the same form. The second light-emitting device may include, for example, a light-emitting element having a peak emission wavelength in the range of 400 nm to 490 nm and a first phosphor having a peak emission wavelength in the range of 480 nm to less than 580 nm, but not including a second phosphor. The first phosphor may include the same phosphor as the first phosphor described above. The second light-emitting device may include a device that includes a light-emitting element having a peak emission wavelength in the range of 400 nm to 490 nm and a rare earth aluminate phosphor having a composition represented by formula (1A) as the first phosphor, but not including a second phosphor, and emits light having a first brightness ratio Ls / L exceeding 0.9, or a second brightness ratio B / A exceeding 0.104, and a correlated color temperature in the range of 5000 K to 6500 K.

[0194] vehicle

[0195] The vehicle of the third embodiment may be a vehicle that can be equipped with the above-mentioned light emitting device or headlamp. Examples of the vehicle that can be equipped with the above-mentioned light emitting device or headlamp include road transport vehicles such as two-wheeled motor vehicles and four-wheeled motor vehicles, railway vehicles, tractors such as land leveling / transportation / loading machines, and vehicles used in vehicle-type engineering machinery such as excavators such as excavation machines, etc.

[0196] Embodiments of the present invention include the following light emitting devices, headlights, and vehicles.

[0197] [Item 1]

[0198] A light emitting device comprising:

[0199] A light emitting element having a peak emission wavelength in the range of 400 nm to 490 nm, and

[0200] wavelength conversion member,

[0201] The wavelength conversion member includes a first phosphor having a peak emission wavelength in a range of 480 nm to less than 580 nm, and a second phosphor having a peak emission wavelength in a range of 580 nm to 680 nm and having a composition different from that of the first phosphor.

[0202] The light-emitting device emits light having a first brightness ratio Ls / L of less than 0.9 derived from the following formula (1), wherein the first brightness ratio Ls / L is a ratio of a first effective radiation brightness Ls of the light emitted by the light-emitting device in a range of 380 nm to 780 nm to a brightness L of the light emitted by the light-emitting device in a range of 380 nm to 780 nm, wherein the first effective radiation brightness Ls takes into account the relative visibility curve of the human photopic vision standard specified by CIE (International Commission on Illumination) and the spectral sensitivity of the human S cone, and the brightness L takes into account the relative visibility curve of the human photopic vision standard specified by CIE (International Commission on Illumination).

[0203] The first phosphor includes a rare earth aluminate phosphor having a composition represented by the following formula (1A).

[0204]

[0205] (In formula (1), S(λ) is the spectral radiation brightness of the light emitted by the light-emitting device, V(λ) is the relative visibility curve of the human photopic vision standard specified by CIE (International Commission on Illumination), and Gs(λ) is the spectral sensitivity of the human S cone within the range of wavelength λnm from 380nm to 550nm.)

[0206] Ln 1 3-e Ce e (Al 1-a Ga a )5O 12 (1A)

[0207] (In formula (1A), Ln 1 is at least one element selected from Y, Gd, Tb and Lu, and a and e satisfy 0≤a≤0.5, 0.019≤e≤0.2. )

[0208] [Item 2]

[0209] The light emitting device according to Item 1 emits light having a correlated color temperature of 1800K or higher and 5000K or lower.

[0210] [Item 3]

[0211] The light-emitting device according to item 1 or 2, wherein the full width at half maximum of the light-emitting spectrum of the first phosphor is within a range of not less than 90 nm and not more than 125 nm.

[0212] [Item 4]

[0213] A light-emitting device according to any one of items 1 to 3, wherein the half-value width of the light-emitting spectrum of the above-mentioned second phosphor is in the range of greater than 3 nm and less than 15 nm, or the half-value width of the light-emitting spectrum is in the range of greater than 60 nm and less than 120 nm.

[0214] [Item 5]

[0215] The light-emitting device according to any one of items 1 to 4, wherein the rare earth aluminate phosphor having the composition represented by the above formula (1A) has an average particle size measured by a Fisher particle counter method in the range of 15 μm to 40 μm.

[0216] [Item 6]

[0217] A light-emitting device according to any one of items 1 to 5, wherein the first phosphor includes a rare earth aluminate phosphor having a composition represented by the above formula (1A), and further includes a first nitride phosphor having a composition represented by the following formula (1B).

[0218] La w Ln 2 x Ce z Si6N y (1B)

[0219] (In formula (1B), Ln 2 It must contain at least one selected from Y and Gd, and optionally contains at least one selected from Sc and Lu, and the Ln contained in 1 mol is 2 When the element is set to 100 mol%, Ln 2 The total amount of Y and Gd contained in is 90 mol% or more, and w, x, y and z satisfy 1.2≤w≤2.2, 0.5≤x≤1.2, 10≤y≤12, 0.5≤z≤1.2, 1.80<w+x<2.40, 2.9≤w+x+z≤3.1. )

[0220] [Item 7]

[0221] The light-emitting device according to any one of items 1 to 6, wherein the second phosphor comprises at least one selected from the following:

[0222] A second nitride phosphor having a composition represented by the following formula (2A), a third nitride phosphor having a composition represented by the following formula (2B), a fluoride phosphor having a composition represented by the following formula (2C), a fluoride phosphor having a composition different from that of the following formula (2C) and having a composition represented by the following formula (2C'), and an α-sialon phosphor having a composition represented by the following formula (2G).

[0223] M 12Si5N8:Eu(2A)

[0224] (In formula (2A), M 1 It is an alkaline earth metal element containing at least one selected from Ca, Sr and Ba. )

[0225] Sr q Ca s Al t Si u N v :Eu(2B)

[0226] (In formula (2B), q, s, t, u and v satisfy 0≤q<1, 0<s≤1, q+s≤1, 0.9≤t≤1.1, 0.9≤u≤1.1, 2.5≤v≤3.5 respectively.)

[0227] A c [M 2 1-b Mn 4＋ b F d ](2C)

[0228] (In formula (2C), A comprises a ＋ , Li ＋ 、Na ＋ , Rb ＋ , Cs ＋ and NH4 ＋ At least one of M 2 Contains at least one element selected from Group 4 elements and Group 14 elements, b satisfies 0<b<0.2, and c is [M 2 1-b Mn 4＋ b F d ]The absolute value of the charge of the ion, d satisfies 5<d<7. )

[0229] A' c’ [M 2 ' 1-b’ Mn 4＋ b’ F d’ ](2C')

[0230] (In formula (2C'), A' comprises a ＋ , Li ＋ 、Na ＋ , Rb ＋ , Cs ＋ and NH4 ＋ At least one of M 2' contains at least one element selected from Group 4 elements, Group 13 elements and Group 14 elements, b' satisfies 0<b'<0.2, c' is [M 2 ' 1-b’ Mn 4＋ b’ F d’ ]The absolute value of the charge of the ion, d' satisfies 5<d'<7. )

[0231] M 8 v3 Si 12-(w3＋x3) Al w3＋x3 O x3 N 16-x3 :Eu(2G)

[0232] (In formula (2G), M 8 Contains at least one element selected from Li, Mg, Ca, Sr, Y and lanthanide elements (except La and Ce), and v3, w3 and x3 satisfy 0<v3≤2.0, 2.0≤w3≤6.0, 0≤x3≤1.0 respectively. )

[0233] [Item 8]

[0234] A light-emitting device according to any one of items 1 to 7, wherein the wavelength conversion component comprises a wavelength converter comprising the first phosphor, the second phosphor, and a translucent material, and the total amount of the first phosphor and the second phosphor is in the range of not less than 50 parts by mass and not more than 500 parts by mass relative to 100 parts by mass of the translucent material in the wavelength converter.

[0235] [Item 9]

[0236] The light emitting device according to any one of items 1 to 8, wherein the wavelength converting member comprises a wavelength converting body including the first phosphor and the second phosphor, and a light-transmitting material,

[0237] The wavelength converter includes a high-concentration layer having a high filling rate of the first phosphor and the second phosphor, and a low-concentration layer having a low filling rate of the first phosphor and the second phosphor.

[0238] The high concentration layer is disposed on the light emitting element side.

[0239] [Item 10]

[0240] A headlamp comprising the light emitting device according to any one of items 1 to 9 above.

[0241] [Item 11]

[0242] The headlamp according to item 10 includes two or more light emitting devices having different values ​​of the first brightness ratio Ls / L.

[0243] [Item 12]

[0244] A headlamp comprising two or more light emitting devices, namely a first light emitting device and a second light emitting device.

[0245] The first light-emitting device comprises the light-emitting device described in any one of items 1 to 9,

[0246] The second light-emitting device emits light having a first brightness ratio Ls / L exceeding 0.9 derived from the following formula (1), wherein the first brightness ratio Ls / L is a ratio of the first effective radiant brightness of the light emitted by the light-emitting device between 380 nm and 780 nm to the brightness L of the light emitted by the light-emitting device between 380 nm and 780 nm, wherein the first effective radiant brightness takes into account the standard relative visibility curve for human photopic vision specified by CIE (International Commission on Illumination) and the spectral sensitivity of the human S cone, and the brightness L takes into account the above-mentioned standard relative visibility curve for human photopic vision.

[0247]

[0248] (In formula (1), S(λ) is the spectral radiation brightness of the light emitted by the light-emitting device, V(λ) is the relative visibility curve of the human photopic vision standard specified by CIE (International Commission on Illumination), and Gs(λ) is the spectral sensitivity of the human S cone within the range of wavelength λnm from 380nm to 550nm.)

[0249] [Item 13]

[0250] A light emitting device comprising:

[0251] A light emitting element having a peak emission wavelength in the range of 400 nm to 490 nm, and

[0252] wavelength conversion member,

[0253] The wavelength conversion member includes a first phosphor having a peak emission wavelength in a range of 480 nm to less than 580 nm, and a second phosphor having a peak emission wavelength in a range of 580 nm to 680 nm and having a composition different from that of the first phosphor.

[0254] The light-emitting device emits light having a second brightness ratio B / A of 0.104 or less derived from the following formula (2), wherein the second brightness ratio B / A is a ratio of a second effective radiation brightness B of the light emitted by the light-emitting device in a range of 300 nm to 800 nm to a radiation brightness A of the light emitted by the light-emitting device in a range of 300 nm to 800 nm, wherein the second effective radiation brightness B takes into account a scattering intensity curve relative to wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1.

[0255] The first phosphor includes a rare earth aluminate phosphor having a composition represented by the following formula (1A).

[0256]

[0257] (In formula (2), S(λ) is the spectral radiation brightness of the light emitted by the light emitting device, and Dc(λ) is a scattering intensity curve relative to wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1 in Rayleigh scattering.)

[0258] Ln 1 3-e Ce e (Al 1-a Ga a )5O 12 (1A)

[0259] (In formula (1A), Ln 1 is at least one element selected from Y, Gd, Tb and Lu, and a and e satisfy 0≤a≤0.5, 0.019≤e≤0.2. )

[0260] [Item 14]

[0261] The light emitting device according to Item 13 emits light having a correlated color temperature of 1800K or higher and 5000K or lower.

[0262] [Item 15]

[0263] The light-emitting device according to item 13 or 14, wherein the full width at half maximum of the light-emitting spectrum of the first phosphor is within a range of not less than 90 nm and not more than 125 nm.

[0264] [Item 16]

[0265] A light-emitting device according to any one of items 13 to 15, wherein the half-value width of the light-emitting spectrum of the above-mentioned second phosphor is in the range of greater than 3 nm and less than 15 nm, or the half-value width of the light-emitting spectrum is in the range of greater than 60 nm and less than 120 nm.

[0266] [Item 17]

[0267] A light-emitting device according to any one of items 13 to 16, wherein the first phosphor comprises a rare earth aluminate phosphor having a composition represented by the above formula (1A), and further comprises a first nitride phosphor having a composition represented by the following formula (1B).

[0268] La w Ln 2 x Ce z Si6N y :(1B)

[0269] (In formula (II), Ln 2 It must contain at least one selected from Y and Gd, and optionally contains at least one selected from Sc and Lu, and the Ln contained in 1 mol is 2 When the element is set to 100 mol%, Ln 2 The total amount of Y and Gd contained in is 90 mol% or more, and w, x, y and z satisfy 1.2≤w≤2.2, 0.5≤x≤1.2, 10≤y≤12, 0.5≤z≤1.2, 1.80<w+x<2.40, 2.9≤w+x+z≤3.1. )

[0270] [Item 18]

[0271] The light-emitting device according to any one of items 13 to 17, wherein the second phosphor comprises at least one selected from the following:

[0272] A second nitride phosphor having a composition represented by the following formula (2A), a third nitride phosphor having a composition represented by the following formula (2B), a fluoride phosphor having a composition represented by the following formula (2C), a fluoride phosphor having a composition different from that of the following formula (2C) and having a composition represented by the following formula (2C'), and an α-sialon phosphor having a composition represented by the following formula (2G).

[0273] M 1 2Si5N8:Eu(2A)

[0274] (In formula (2A), M 1 It is an alkaline earth metal element containing at least one selected from Ca, Sr and Ba. )

[0275] Sr q Ca s Al t Si u N v :Eu(2B)

[0276] (In formula (2B), q, s, t, u and v satisfy 0≤q<1, 0<s≤1, q+s≤1, 0.9≤t≤1.1, 0.9≤u≤1.1, 2.5≤v≤3.5 respectively.)

[0277] A c [M 2 1-b Mn 4＋ b F d ](2C)

[0278] (In formula (2C), A comprises a ＋ , Li ＋ 、Na ＋ , Rb ＋ , Cs ＋ and NH4 ＋ At least one of M 2 Contains at least one element selected from Group 4 elements and Group 14 elements, b satisfies 0<b<0.2, and c is [M 2 1-b Mn 4＋ b F d ]The absolute value of the charge of the ion, d satisfies 5<d<7. )

[0279] A' c’ [M 2 ' 1-b’ Mn 4＋ b’ F d’ ](2C')

[0280] (In formula (2C'), A' comprises a ＋ , Li ＋ 、Na ＋ , Rb ＋ , Cs ＋ and NH4 ＋ At least one of M 2 ' contains at least one element selected from Group 4 elements, Group 13 elements and Group 14 elements, b' satisfies 0<b'<0.2, c' is [M 2 ' 1-b’ Mn 4＋ b’ F d’ ]The absolute value of the charge of the ion, d' satisfies 5<d'<7. )

[0281] M 8 v3 Si 12-(w3＋x3) Al w3＋x3 O x3 N 16-x3:Eu(2G)

[0282] (In formula (2G), M 8 Contains at least one element selected from Li, Mg, Ca, Sr, Y and lanthanide elements (except La and Ce), and v3, w3 and x3 satisfy 0<v3≤2.0, 2.0≤w3≤6.0, 0≤x3≤1.0 respectively. )

[0283] [Item 19]

[0284] The light-emitting device according to any one of items 13 to 18, wherein the average particle size of the rare earth aluminate phosphor having the composition represented by the above formula (1A) measured by a Fisher particle counter method is within a range of 15 μm to 40 μm.

[0285] [Item 20]

[0286] A light-emitting device according to any one of items 13 to 19, wherein the wavelength conversion component comprises a wavelength converter comprising the first phosphor, the second phosphor, and a light-transmitting material, and the total amount of the first phosphor and the second phosphor is within a range of not less than 50 parts by mass and not more than 500 parts by mass relative to 100 parts by mass of the light-transmitting material in the wavelength converter.

[0287] [Item 21]

[0288] The light emitting device according to any one of items 13 to 20, wherein the wavelength conversion member comprises a wavelength conversion body including the first phosphor and the second phosphor, and a light-transmitting material,

[0289] The wavelength converter includes a high-concentration layer having a high filling rate of the first phosphor and the second phosphor, and a low-concentration layer having a low filling rate of the first phosphor and the second phosphor.

[0290] The high concentration layer is disposed on the light emitting element side.

[0291] [Item 22]

[0292] A headlamp comprising the light emitting device according to any one of items 13 to 21 above.

[0293] [Item 23]

[0294] The headlamp according to Item 22 includes two or more light emitting devices having different values ​​of the second brightness ratio B / A.

[0295] [Item 24]

[0296] A headlamp comprising two or more light emitting devices, namely a first light emitting device and a second light emitting device.

[0297] The first light-emitting device includes the light-emitting device described in any one of items 13 to 21 above,

[0298] The second light-emitting device emits light with a second brightness ratio B / A exceeding 0.104 derived from the following formula (2), wherein the second brightness ratio B / A is a ratio of the second effective radiation brightness B of the light emitted by the light-emitting device in the range of greater than 300nm and less than 800nm ​​to the radiation brightness A of the light emitted by the light-emitting device in the range of greater than 300nm and less than 800nm, and the second effective radiation brightness B takes into account the scattering intensity curve relative to wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300nm is set to 1.

[0299]

[0300] (In formula (2), S(λ) is the spectral radiation brightness of the light emitted by the light emitting device, and Dc(λ) is a scattering intensity curve relative to wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1 in Rayleigh scattering.)

[0301] [Item 25]

[0302] A vehicle comprising the light emitting device according to any one of items 1 to 9 and 13 to 21 above.

[0303] [Item 26]

[0304] A vehicle comprising the headlamp according to any one of items 10 to 12 and 22 to 24 above.

[0305] Example

[0306] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0307] The following first phosphor and second phosphor are used in the light-emitting devices of the examples and comparative examples.

[0308] First phosphor

[0309] As the first phosphor, rare earth aluminate phosphors YAG-1, YAG-2, YAG-3, YAG-4 and YAG-5 were prepared, each having a composition represented by the above formula (1A), Ln represented by the above formula (1A) 1 The molar ratio of Ce contained in the composition (variable e in the above formula (1A)) is the numerical value shown in Table 1. In addition, as the first phosphor, YAG-6 was prepared, which has a composition not included in the above formula (1A), Ln represented by the above formula (1A), 1The molar ratio of Ce contained in the composition is Y and 0.018. As shown in Table 1, these first phosphors have different average particle sizes, CIE chromaticity coordinates (x, y), emission peak wavelengths and half-value full widths measured by the FSSS method. In this specification, the "-" symbol in Table 1 indicates that there is no corresponding item or value.

[0310] Second phosphor

[0311] As the second phosphor, a second nitride phosphor BSESN-1 having a composition represented by the above formula (2A) was prepared. The second phosphor had an average particle size, CIE chromaticity coordinates (x, y), emission peak wavelength, and half-value full width measured by the FSSS method as shown in Table 1.

[0312] Luminescence spectrum of phosphors

[0313] For each phosphor, a quantum efficiency measuring device (QE-2000, manufactured by Otsuka Electronics Co., Ltd.) was used to irradiate each phosphor with light of an excitation wavelength of 450nm, and the emission spectrum at room temperature (about 25°C) was measured. Based on each emission spectrum, the x value and y value in the chromaticity coordinates of CIE1931, the emission peak wavelength, and the half-value full width were measured.

[0314] Average particle size of phosphor

[0315] For each phosphor, the average particle size was measured by the FSSS method using Fisher Sub-Sieve Sizer Model 95 (manufactured by Fisher Scientific). 3 After a certain volume of the phosphor sample is placed in a dedicated tubular container, dry air at a certain pressure is passed through it, and the specific surface area is read based on the differential pressure, which is converted into the average particle size (Fisher Sub-Sieve Sizer's No.).

[0316]

[0317] Embodiment 1~6

[0318] Made Figure 3A and Figure 3B A light-emitting device of the form shown.

[0319] In the configuration process of the light-emitting element, a ceramic substrate made of aluminum nitride is used as the substrate. A light-emitting element is a light-emitting element stacked with a nitride semiconductor layer having a peak emission wavelength of 450nm. As for the size of the light-emitting element, the plane shape is a roughly square of about 1.0 mm square and the thickness is about 0.11 mm. The light-emitting element is configured in such a way that the light-emitting surface becomes the substrate side, and a flip-chip mounting is performed by using a bump of a conductive member formed of Au. In addition, a semiconductor element is flip-chip mounted by using a bump of a conductive member formed of Au at a distance from the light-emitting element.

[0320] As a light-transmitting material, silicone resin a (Shore A hardness 70) is used. In the formation process of the wavelength conversion component including the wavelength converter, the first phosphor and the second phosphor are used in the combination shown in Table 2 relative to 100 parts by mass of silicone resin a as a light-transmitting material. In Table 2, the total amount of phosphors represents the total amount of the first phosphor and the second phosphor relative to 100 parts by mass of silicone resin a. In addition, in Table 2, the mass ratio (mass %) of the first phosphor and the mass ratio (mass %) of the second phosphor represent the mass ratio of the first phosphor and the mass ratio of the second phosphor when the total content of the first phosphor and the second phosphor is set to 100 mass %. The content of the first phosphor or the content of the second phosphor contained in the light-emitting device can be calculated by multiplying the product of the total amount (mass parts) of the first phosphor and the second phosphor and the mass ratio (mass %) of each of the first phosphor and the second phosphor and dividing it by 100. As a light-transmitting body, a light-transmitting body made of borosilicate glass is provided, which is a roughly square shape with a length and width of about 0.15 mm larger than the plane shape of the light-emitting element, a plane shape of about 1.15 mm square, and a thickness of about 0.10 mm. A wavelength converter composition is printed on one side of the roughly square shape of the light-transmitting body by a printing method, and heated at 180° C. for 2 hours to cure the wavelength converter composition to form a layered wavelength converter with a thickness of about 80 μm, forming a wavelength conversion component in which a layered or plate-like wavelength converter and a light-transmitting body are integrated. In this specification, the Shore A hardness of the silicone resin is measured using a type A durometer (product name: GS-709G, manufactured by TECLOCK) in accordance with JIS K6253.

[0321] In the bonding process of the light-emitting element and the wavelength conversion component, an adhesive containing silicone resin is used to bond one side of the wavelength conversion component that is approximately a square with a planar shape of about 1.15 mm square to one side of the light-emitting element that is approximately a square with a planar shape of about 1.0 mm square, thereby forming an adhesive layer between the light-emitting element and the wavelength conversion component.

[0322] In the step of forming the covering member, a covering member composition containing dimethyl silicone resin and titanium oxide particles, and containing 30 parts by mass of titanium oxide particles relative to 100 parts by mass of the dimethyl silicone resin, is prepared. The light-emitting element disposed on the substrate and the side of the wavelength converter including the wavelength converter and the light-transmitting body are covered with the covering member composition, the covering member composition is filled so that the semiconductor element is completely buried in the covering member composition, the covering member composition is cured, the covering member is formed, a resin package is formed, and a light-emitting device is manufactured.

[0323] Comparative Example 1

[0324] A light-emitting device was manufactured in the same manner as in Example 1, except that YAG-6 having a composition not included in the above formula (1A) was used as the first phosphor, and the first phosphor and the second phosphor were used in the blend shown in Table 2.

[0325] The following measurements were performed on each light emitting device. The results are shown in Table 2.

[0326] Luminous spectrum, chromaticity coordinates (x, y), and correlated color temperature (K) of the light-emitting device

[0327] For each light-emitting device, the emission spectrum at room temperature (25°C ± 5°C) was measured using a light measurement system composed of a spectrophotometer (PMA-11, manufactured by Hamamatsu Photonics) and an integrating sphere. Based on the emission spectrum of each light-emitting device, the x value and y value in the chromaticity coordinates of CIE1931 and the correlated color temperature (K) according to JIS Z8725 were measured. Figure 6 Graph 2 shows the emission spectrum of the light-emitting device of Example 1 when the maximum emission intensity is set to 1.

[0328] First brightness ratio Ls / L

[0329] The luminous spectra S(λ) measured for each luminous device are Figure 1A The spectral sensitivity Gs(λ) of the human S cone is obtained according to Figure 1B The obtained relative visibility curve V(λ) of the photopic vision standard for humans specified by CIE was substituted into the above equation (1), and the first brightness ratio Ls / L of the light emitted by each light emitting device was measured.

[0330] Second brightness ratio B / A

[0331] The luminous spectra S(λ) measured for each luminous device are Figure 2 The obtained scattering intensity curve Dc(λ) was substituted into the above formula (2), and the second brightness ratio B / A of the light emitted by each light emitting device was measured.

[0332] Relative luminous flux (%)

[0333] The luminous flux of each light emitting device was measured using a total luminous flux measuring device using an integrating sphere. The luminous flux of the light emitting device of Comparative Example 1 was set as 100%, and the relative luminous flux of each light emitting device other than Comparative Example 1 was calculated.

[0334]

[0335] The light emitting devices of Examples 1 to 6 emit light having a correlated color temperature of 1800K or more and 5000K or less, and emit light having a first luminance ratio Ls / L of 0.9 or less. The light emitting devices of Examples 1 to 6 can emit light with reduced glare.

[0336] The light emitting devices of Examples 1 to 6 emit light having a second brightness ratio B / A of 0.104 or less. The light emitting devices of Examples 1 to 6 suppress light scattering and can emit light that reaches a relatively far distance.

[0337] The light-emitting devices of Examples 1 to 6 include a first phosphor having a composition represented by the above formula (1A), wherein the variable e representing the molar ratio of the activating element Ce in the above formula (1A) satisfies a range of greater than 0.019 and less than 0.2 (0.019≤e≤0.2), more specifically, a range of greater than 0.025 and less than 0.112. Compared with the first phosphor having a composition not included in the composition formula represented by the above formula (1A), the content of the first phosphor contained in the light-emitting device can be reduced (the amount obtained by dividing the product of the total amount of the phosphor and the mass ratio of the first phosphor by 100). In addition, the light-emitting devices of Examples 1 to 6 include a first phosphor having a composition represented by the above formula (1A), in which the variable e representing the molar ratio of the activating element Ce satisfies the range of greater than 0.019 and less than 0.2 (0.019≤e≤0.2). Therefore, the total amount of phosphor contained in the wavelength conversion component can be less than the wavelength conversion component used in the light-emitting device of Comparative Example 1. Even when the total amount of phosphor is small, the light-emitting device has a hue of CIE chromaticity coordinates within the target range and emits light having a first brightness ratio Ls / L of less than 0.9 and a second brightness ratio B / A of less than 0.104.

[0338] Reliability evaluation test, quantification of the peeling ratio

[0339] Reliability evaluation was performed on each light-emitting device. The results are shown in Table 3. As a reliability evaluation, a reliability evaluation test was conducted in an environmental testing machine at 85°C and 85% relative humidity for 700 hours at a current of 1200mA, with the light-emitting device repeatedly turned on (ON) and off (OFF) every 30 minutes. After the reliability evaluation test, the wavelength conversion component of the light-emitting device was observed under a microscope, and the ratio of peeling between the wavelength converter and the light-transmitting body was quantified to evaluate the durability. Figure 3B In FIG. 1 , the ratio of the peeling occurring between the wavelength converter 41 and the light-transmitting body 42 of the wavelength converter 40 is numerically expressed.

[0340] The quantification of the peeling ratio was performed using "Image J", an open-source public domain image analysis processing software developed by the National Institutes of Health in the United States. The photograph obtained by photographing the light-emitting device from the side of the light-transmitting body with a microscope was cut to only show the light-transmitting body surface, separated into the three primary colors RGB of the color photograph obtained by photographing the light-transmitting body, and only G of the three primary colors RGB was extracted. This is because the light contrast (brightness and darkness) of G tends to become clear and distinct. The contrast of the photograph obtained by extracting only G from the color photograph obtained by photographing the light-transmitting body of the light-emitting device was adjusted to enhance the peeling portion generated between the wavelength converter and the light-transmitting body, and the peeling portion was binarized. The ratio of the total area of ​​the peeling portion in the light-transmitting body surface to the area of ​​the light-transmitting body surface was calculated in the form of the peeling ratio (peeling surface / light-transmitting body surface (%)). The calculated peeling ratio is shown in Table 3. Table 3 also shows the type of the first phosphor represented by the above formula (1A) contained in the wavelength conversion component of each light-emitting device and the molar ratio of Ce contained in the first phosphor (variable e in the above formula (1A)). In addition, Figure 8 A photograph showing a binary image of the light-transmitting body surface of the light-emitting device of Example 1 after a reliability evaluation test for 700 hours is shown. Fig. 9 A photograph showing a binarized surface of the light-transmitting body of the light-emitting device of Comparative Example 1 after a reliability evaluation test for 700 hours is shown.

[0341] For each light emitting device after the reliability evaluation test, the first brightness ratio and the second brightness ratio were calculated in the same manner as before the reliability evaluation test. In addition, the emission spectrum of each light emitting device after the reliability evaluation test was measured in the same manner as before the reliability evaluation test, and the x value and the y value in the chromaticity coordinate of CIE1931 were measured based on the emission spectrum of each light emitting device, and the correlated color temperature (K) was measured in accordance with JIS Z8725. Specifically, the x value and the y value in the CIE chromaticity coordinate of the mixed color light emitted from the light emitting device in the initial state before the reliability evaluation test were set as the x1 value and the y1 value, and the light emitting device was repeatedly turned on (ON) and off (OFF) every 30 minutes in an environmental test machine at 85°C and a relative humidity of 85% for 700 hours at a current of 1200 mA, and then the x2 and y2 values ​​in the CIE chromaticity coordinate of the mixed color light emitted from the light emitting device were measured, and the absolute values ​​of the difference Δx between the x1 value and the x2 value and the difference Δy between the y1 value and the y2 value were calculated. Figure 7 Graph 2 shows the emission spectrum of the light emitting device of Example 1 after the reliability evaluation test when the maximum emission intensity is set to 1.

[0342]

[0343] The light emitting devices of Examples 1 to 6 also emit light with a correlated color temperature of 1800K or more and 5000K or less, and emit light with a first brightness ratio Ls / L of 0.9 or less after a reliability evaluation test for 700 hours in an environmental test chamber at 85°C and a relative humidity of 85%. The light emitting devices of Examples 1 to 6 can emit light with reduced glare.

[0344] The light emitting devices of Examples 1 to 6 also emit light having a second brightness ratio B / A of 0.104 or less after a reliability evaluation test of 700 hours in an environmental test chamber at 85°C and 85% relative humidity. The light emitting devices of Examples 1 to 6 suppress light scattering and can emit light that reaches a relatively far distance.

[0345] In addition, the light-emitting devices of Examples 1 to 6 include a first phosphor having a composition represented by the above formula (1A), and the variable e representing the molar ratio of the activating element Ce in the above formula (1A) satisfies the range of greater than 0.019 and less than 0.2 (0.019≤e≤0.2). Therefore, the total amount of phosphor contained in the wavelength conversion component can be set to a smaller amount than the wavelength conversion component used in the light-emitting device of Comparative Example 1. After 700 hours of reliability evaluation test in an environmental testing machine at 85°C and a relative humidity of 85%, the proportion of peeling between the wavelength converter 41 and the light-transmitting body 42 of the wavelength conversion component 40 is less than that of the light-emitting device of Comparative Example 1, which can improve durability. In addition, the light-emitting devices of Examples 1 to 6 include a first phosphor having a composition represented by the above formula (1A), and the variable e representing the molar ratio of the activating element Ce in the above formula (1A) satisfies the range of greater than 0.019 and less than 0.2 (0.019≤e≤0.2). Therefore, the values ​​of Δx and Δy representing the chromaticity change before and after the reliability evaluation test are also smaller than Δx and Δy of the light-emitting device of Comparative Example 1, which can suppress chromaticity shift and improve durability.

[0346] for Figure 6 The light emission spectrum of the light emitting device of Example 1 before the reliability evaluation test is shown in FIG. Figure 7 As for the luminous spectrum of the light-emitting device of Example 1 after the reliability evaluation test shown, the luminous spectrum basically did not change. After 700 hours of reliability evaluation test in an environmental testing machine at 85°C and 85% relative humidity, as described above, light with reduced glare can be emitted, light scattering is suppressed, and light that can reach a farther distance can be emitted.

[0347] In the Figure 8 In the binarized photograph of the light-transmitting body surface of the light-emitting device of Example 1 after the reliability evaluation test for 700 hours, almost no white peeled portion was confirmed. The durability of the light-emitting device was improved.

[0348] In the Fig. 9 In the photograph showing the binarization of the light-transmitting body surface of the light-emitting device of Comparative Example 1 after the reliability evaluation test for 700 hours, a large amount of white was observed indicating the peeling portion between the wavelength converter and the light-transmitting body.

[0349] Industrial Applicability

[0350] The light emitting device of the embodiment of the present disclosure can be used for a headlamp. The headlamp equipped with the light emitting device based on the embodiment of the present disclosure can be used for a road transport vehicle such as a motor two-wheeled vehicle or a motor four-wheeled vehicle, a railway vehicle, a tractor such as a land leveling / transportation / loading machine, or an excavator such as an excavation machine, which is a vehicle used for construction machinery.

Claims

1. A light emitting device comprising: A light emitting element having a peak emission wavelength in the range of 400 nm to 490 nm, and wavelength conversion member, The wavelength conversion member includes a first phosphor having a peak emission wavelength in a range of 480 nm to less than 580 nm, and a second phosphor having a peak emission wavelength in a range of 580 nm to 680 nm and having a composition different from that of the first phosphor. The light emitting device emits light having a first brightness ratio Ls / L of less than 0.9 derived from the following formula (1), wherein the first brightness ratio Ls / L is a ratio of a first effective radiation brightness Ls of the light emitted by the light emitting device in a range of 380 nm to 780 nm to a brightness L of the light emitted by the light emitting device in a range of 380 nm to 780 nm, wherein the first effective radiation brightness Ls takes into account the relative visibility curve of the human photopic vision standard specified by CIE (International Commission on Illumination) and the spectral sensitivity of the human S cone, and the brightness L takes into account the relative visibility curve of the human photopic vision standard specified by CIE (International Commission on Illumination). The first phosphor includes a rare earth aluminate phosphor having a composition represented by the following formula (1A), ， In formula (1), S(λ) is the spectral radiation brightness of the light emitted by the light emitting device, V(λ) is the relative visibility curve of the human photopic vision standard specified by CIE (International Commission on Illumination), Gs(λ) is the spectral sensitivity of the human S cone within the range of wavelength λnm from 380nm to 550nm, Ln 1 3-e Ce e (Al 1-a Ga a )5O 12 (1A) In formula (1A), Ln 1 It is at least one element selected from Y, Gd, Tb and Lu, and a and e satisfy 0≤a≤0.5 and 0.019≤e≤0.

2. 2 . The light-emitting device according to claim 1 , which emits light having a correlated color temperature of 1800 K or higher and 5000 K or lower.

3. The light emitting device according to claim 1 or 2, wherein: The full width at half maximum of the emission spectrum of the first phosphor is within a range of 90 nm to 125 nm.

4. The light emitting device according to any one of claims 1 to 3, wherein: The full width at half maximum of the emission spectrum of the second phosphor is within the range of 3 nm to 15 nm, or the full width at half maximum of the emission spectrum is within the range of 60 nm to 120 nm.

5. The light emitting device according to any one of claims 1 to 4, wherein: The rare earth aluminate phosphor having the composition represented by the formula (1A) has an average particle size measured by a Fisher micrometer method in the range of 15 μm or more and 40 μm or less.

6. The light emitting device according to any one of claims 1 to 5, wherein: The first phosphor includes a rare earth aluminate phosphor having a composition represented by the formula (1A), and further includes a first nitride phosphor having a composition represented by the following formula (1B). to w What z In 2 x Si6N y :What z (1B) In formula (1B), Ln 2 It must contain at least one selected from Y and Gd, and optionally contains at least one selected from Sc and Lu, and the Ln contained in 1 mol is 2 When the element is set to 100 mol%, Ln 2 The total amount of Y and Gd contained in is 90 mol % or more, and w, x, y and z satisfy 1.2≤w≤2.2, 0.5≤x≤1.2, 10≤y≤12, 0.5≤z≤1.2, 1.80<w+x<2.40, and 2.9≤w+x+z≤3.

1.

7. The light emitting device according to any one of claims 1 to 6, wherein: The second phosphor includes at least one selected from the following: A second nitride phosphor having a composition represented by the following formula (2A), a third nitride phosphor having a composition represented by the following formula (2B), a fluoride phosphor having a composition represented by the following formula (2C), a fluoride phosphor having a composition different from that represented by the following formula (2C'), and an α-sialon phosphor having a composition represented by the following formula (2G), <h2 style=";text-align:left;direction:ltr">M<h2 style=";text-align:left;direction:ltr"> 1 <h2 style=";text-align:left;direction:ltr"> 2Si5N8:Eu(2A) In formula (2A), M 1 is an alkaline earth metal element containing at least one selected from Ca, Sr and Ba, Sr. q That s the t And u N v :I(2B) In formula (2B), q, s, t, u and v respectively satisfy 0≤q<1, 0<s≤1, q+s≤1, 0.9≤t≤1.1, 0.9≤u≤1.1, 2.5≤v≤3.5, A c [M 2 1-b Mn 4+ b F d ](2C) In formula (2C), A comprises a ＋ , Li ＋ 、Na ＋ , Rb ＋ , Cs ＋ and NH4 ＋ At least one of M 2 Contains at least one element selected from Group 4 elements and Group 14 elements, b satisfies 0<b<0.2, and c is [M 2 1-b Mn 4＋ b F d ] The absolute value of the charge of the ion, d satisfies 5<d<7, A’ c’ [M 2 ’ 1-b’ Mn 4＋ b’ F d’ ](2C’) In formula (2C'), A' comprises a ＋ , Li ＋ 、Na ＋ , Rb ＋ , Cs ＋ and NH4 ＋ At least one of M 2 ' contains at least one element selected from Group 4 elements, Group 13 elements and Group 14 elements, b' satisfies 0<b'<0.2, c' is [M 2 ' 1-b’ Mn 4＋ b’ F d’ ] The absolute value of the charge of the ion, d' satisfies 5<d'<7, M 8 v3 And 12-(w3＋x3) the w3＋x3 A x3 N 16-x3 :I(2G) In formula (2G), M 8 It contains at least one element selected from Li, Mg, Ca, Sr, Y and lanthanide elements (excluding La and Ce), and v3, w3 and x3 respectively satisfy 0<v3≤2.0, 2.0≤w3≤6.0, and 0≤x3≤1.

0.

8. The light emitting device according to any one of claims 1 to 7, wherein: The wavelength conversion component comprises a wavelength converter including the first phosphor and the second phosphor, and a translucent material, wherein the total amount of the first phosphor and the second phosphor is within a range of 50 parts by mass or more and 500 parts by mass or less relative to 100 parts by mass of the translucent material in the wavelength converter.

9. The light emitting device according to any one of claims 1 to 8, wherein: The wavelength conversion member includes a wavelength conversion body including the first phosphor and the second phosphor, and a light-transmitting material. The wavelength converter includes a high-concentration layer having a high filling rate of the first phosphor and the second phosphor, and a low-concentration layer having a low filling rate of the first phosphor and the second phosphor. The high concentration layer is disposed on the light emitting element side. 10 . A headlamp comprising the light emitting device according to claim 1 . 11 . The headlamp according to claim 10 , comprising two or more light emitting devices having different values ​​of the first brightness ratio Ls / L.

12. A headlamp comprising two or more light emitting devices, namely a first light emitting device and a second light emitting device, The first light emitting device includes the light emitting device according to any one of claims 1 to 9, The second light-emitting device emits light having a first brightness ratio Ls / L exceeding 0.9 derived from the following formula (1), wherein the first brightness ratio Ls / L is a ratio of the first effective radiation brightness of the light emitted by the light-emitting device between 380 nm and 780 nm to the brightness L of the light emitted by the light-emitting device between 380 nm and 780 nm, wherein the first effective radiation brightness takes into account the relative visibility curve of the human photopic vision standard specified by CIE (International Commission on Illumination) and the spectral sensitivity of the human S cone, and the brightness L takes into account the relative visibility curve of the human photopic vision standard, ， In formula (1), S(λ) is the spectral radiation brightness of the light emitted by the light-emitting device, V(λ) is the standard relative visibility curve of human photopic vision specified by CIE (International Commission on Illumination), and Gs(λ) is the spectral sensitivity of the human S cone within the range of wavelength λnm above 380nm and below 550nm.

13. A light emitting device comprising: A light emitting element having a peak emission wavelength in the range of 400 nm to 490 nm, and wavelength conversion member, The wavelength conversion member includes a first phosphor having a peak emission wavelength in a range of 480 nm to less than 580 nm, and a second phosphor having a peak emission wavelength in a range of 580 nm to 680 nm and having a composition different from that of the first phosphor. The light emitting device emits light having a second brightness ratio B / A of 0.104 or less derived from the following formula (2), wherein the second brightness ratio B / A is a ratio of a second effective radiation brightness B of the light emitting device in a range of 300 nm to 800 nm to a radiation brightness A of the light emitting device in a range of 300 nm to 800 nm, wherein the second effective radiation brightness B takes into account a scattering intensity curve relative to wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1. The first phosphor includes a rare earth aluminate phosphor having a composition represented by the following formula (1A), ， In formula (2), S(λ) is the spectral radiation brightness of the light emitted by the light emitting device, and Dc(λ) is the scattering intensity curve relative to wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1 in Rayleigh scattering. Ln 1 3-e Ce e (Al 1-a Ga a )5O 12 (1A) In formula (1A), Ln 1 It is at least one element selected from Y, Gd, Tb and Lu, and a and e satisfy 0≤a≤0.5 and 0.019≤e≤0.

2. The light emitting device according to claim 13 , which emits light having a correlated color temperature of 1800K or more and 5000K or less.

15. The light emitting device according to claim 13 or 14, wherein: The full width at half maximum of the emission spectrum of the first phosphor is within a range of 90 nm to 125 nm.

16. The light emitting device according to any one of claims 13 to 15, wherein: The full width at half maximum of the emission spectrum of the second phosphor is within the range of 3 nm to 15 nm, or the full width at half maximum of the emission spectrum is within the range of 60 nm to 120 nm.

17. The light emitting device according to any one of claims 13 to 16, wherein: The first phosphor includes a rare earth aluminate phosphor having a composition represented by the formula (1A), and further includes a first nitride phosphor having a composition represented by the following formula (1B). to w What z In 2 x Si6N y :What z (1B) In formula (1B), Ln 2 It must contain at least one selected from Y and Gd, and optionally contains at least one selected from Sc and Lu, and the Ln contained in 1 mol is 2 When the element is set to 100 mol%, Ln 2 The total amount of Y and Gd contained in the reaction mixture is 90 mol% or more, and w, x, y and z satisfy 1.2≤w≤2.2, 0.5≤x≤1.2, 10≤y≤12, 0.5≤z≤1.2, 1.80<w+x<2.40, and 2.9≤w+x+z≤3.

1.

18. The light emitting device according to any one of claims 13 to 17, wherein: The second phosphor includes at least one selected from the following: A second nitride phosphor having a composition represented by the following formula (2A), a third nitride phosphor having a composition represented by the following formula (2B), a fluoride phosphor having a composition represented by the following formula (2C), a fluoride phosphor having a composition different from that represented by the following formula (2C'), and an α-sialon phosphor having a composition represented by the following formula (2G), <h2 style=";text-align:left;direction:ltr">M<h2 style=";text-align:left;direction:ltr"> 1 <h2 style=";text-align:left;direction:ltr"> 2Si5N8:Eu(2A) In formula (2A), M 1 is an alkaline earth metal element containing at least one selected from Ca, Sr and Ba, Sr. q That s the t And u N v :I(2B) In formula (2B), q, s, t, u and v respectively satisfy 0≤q<1, 0<s≤1, q+s≤1, 0.9≤t≤1.1, 0.9≤u≤1.1, 2.5≤v≤3.5, A c [M 2 1-b Mn 4＋ b F d ](2C) In formula (2C), A comprises a ＋ , Li ＋ 、Na ＋ , Rb ＋ , Cs ＋ and NH4 ＋ At least one of M 2 Contains at least one element selected from Group 4 elements and Group 14 elements, b satisfies 0<b<0.2, and c is [M 2 1-b Mn 4＋ b F d ] The absolute value of the charge of the ion, d satisfies 5<d<7, A’ c’ [M 2 ’ 1-b’ Mn 4＋ b’ F d’ ](2C’) In formula (2C'), A' comprises a ＋ , Li ＋ 、Na ＋ , Rb ＋ , Cs ＋ and NH4 ＋ At least one of M 2’ Contains at least one element selected from Group 4 elements, Group 13 elements and Group 14 elements, b' satisfies 0<b'<0.2, c' is [M 2 ' 1-b’ Mn 4＋ b’ F d’ ] The absolute value of the charge of the ion, d' satisfies 5<d'<7, M 8 v3 And 12-(w3＋x3) the w3＋x3 A x3 N 16-x3 :I(2G) In formula (2G), M 8 It contains at least one element selected from Li, Mg, Ca, Sr, Y and lanthanide elements (excluding La and Ce), and v3, w3 and x3 respectively satisfy 0<v3≤2.0, 2.0≤w3≤6.0, and 0≤x3≤1.

0.

19. The light emitting device according to any one of claims 13 to 18, wherein: The rare earth aluminate phosphor having the composition represented by the formula (1A) has an average particle size measured by a Fisher micrometer method in the range of 15 μm or more and 40 μm or less.

20. The light emitting device according to any one of claims 13 to 19, wherein: The wavelength conversion component comprises a wavelength converter including the first phosphor and the second phosphor, and a translucent material, wherein the total amount of the first phosphor and the second phosphor is within a range of 50 parts by mass or more and 500 parts by mass or less relative to 100 parts by mass of the translucent material in the wavelength converter.

21. The light emitting device according to any one of claims 13 to 20, wherein: The wavelength conversion member includes a wavelength conversion body including the first phosphor and the second phosphor, and a light-transmitting material. The wavelength converter includes a high-concentration layer having a high filling rate of the first phosphor and the second phosphor, and a low-concentration layer having a low filling rate of the first phosphor and the second phosphor. The high concentration layer is disposed on the light emitting element side.

22. A headlamp comprising the light emitting device according to any one of claims 13 to 21.

23. The headlamp according to claim 22, comprising two or more light emitting devices having different values ​​of the second brightness ratio B / A.

24. A headlamp comprising two or more light emitting devices, namely a first light emitting device and a second light emitting device, The first light emitting device includes the light emitting device according to any one of claims 13 to 21, The second light-emitting device emits light having a second brightness ratio B / A exceeding 0.104 derived from the following formula (2), wherein the second brightness ratio B / A is a ratio of a second effective radiation brightness B of the light emitted by the light-emitting device in a range of 300 nm to 800 nm to a radiation brightness A of the light emitted by the light-emitting device in a range of 300 nm to 800 nm, wherein the second effective radiation brightness B takes into account a scattering intensity curve relative to wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1. ， In formula (2), S(λ) is the spectral radiation brightness of the light emitted by the light emitting device, and Dc(λ) is a scattering intensity curve relative to wavelength when the scattering intensity of Rayleigh scattering at a wavelength of 300 nm is set to 1 in Rayleigh scattering.

25. A vehicle comprising the light emitting device according to any one of claims 1 to 9 and 13 to 21.

26. A vehicle comprising the headlamp according to any one of claims 10 to 12 and 22 to 24.

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