US20070224076A1 - Phosphor and Light-Emitting Device Using Same - Google Patents

Phosphor and Light-Emitting Device Using Same Download PDF

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Publication number
US20070224076A1
US20070224076A1 US11/570,814 US57081405A US2007224076A1 US 20070224076 A1 US20070224076 A1 US 20070224076A1 US 57081405 A US57081405 A US 57081405A US 2007224076 A1 US2007224076 A1 US 2007224076A1
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Prior art keywords
phosphor
light
element selected
group
emitting device
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Abandoned
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US11/570,814
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English (en)
Inventor
Hiroaki Tanno
Shuxiu Zhang
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Daiden Co Inc
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Daiden Co Inc
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Assigned to DAIDEN CO., LTD. reassignment DAIDEN CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TANNO, HIROAKI, ZHANG, SHUXIU
Publication of US20070224076A1 publication Critical patent/US20070224076A1/en
Abandoned legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
    • C09K11/7728—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing europium
    • C09K11/7737—Phosphates
    • C09K11/7738—Phosphates with alkaline earth metals

Definitions

  • the present invention pertains to a phosphor and a light-emitting device using same.
  • the present invention pertains to a novel phosphor capable of exhibiting strong light emissions over a wide excitation wavelength range, and a light-emitting device using such a phosphor.
  • the present invention pertains to a novel phosphor that provides stronger light emission intensities under ultraviolet excitation than are obtained from a conventional blue phosphor of europium-activated barium-magnesium-aluminum oxide phosphor (may be called “BAM phosphor” in what follows), and a light-emitting device using such a phosphor.
  • a conventional blue phosphor of europium-activated barium-magnesium-aluminum oxide phosphor may be called “BAM phosphor” in what follows
  • BAM phosphor europium-activated barium-magnesium-aluminum oxide phosphor
  • the present invention also pertains to a novel phosphor that is well-suited for use as a blue phosphor in products such as white LEDs and fluorescent lamps using an ultraviolet excitation source, and a light-emitting device using such a phosphor.
  • the present invention further pertains to a novel phosphor that can be used as a blue phosphor in products such as PDPs (plasma display panels) having vacuum ultraviolet light as an excitation source, and a light-emitting device using such a phosphor.
  • PDPs plasma display panels
  • phosphors undergo excitation by electromagnetic waves such as ultraviolet light, electron beams, and x-rays, and thereby emit light in the near-ultraviolet to visible range.
  • electromagnetic waves such as ultraviolet light, electron beams, and x-rays
  • these phosphors may provide a variety of spectral distributions, so that in combination with an appropriate excitation source, a wide variety of phosphors have been developed.
  • blue phosphors have an especially profound impact on lamp characteristics, and of the three color phosphors, the blue phosphors are particularly important.
  • BAM phosphors are well-known as blue phosphors, and are widely used in fluorescent lamps and as PDP phosphors. See, The Phosphor Handbook (Phosphor Research Society [Keikotai Dougakukai], Ohm-sha, 1987, pp. 225-226 and 332-334).
  • White LEDs are more energy-efficient and have a longer lifespan than fluorescent lamps, and because they do not use mercury, they have the advantage of being much easier on the environment.
  • One-chip type a single type of LED
  • multi-chip type multiple types of LEDs with different colors
  • one-chip type a blue LED or an ultraviolet LED is used as the phosphor excitation light source, and the light emitted by the phosphor is used.
  • multi-chip type multiple types of LEDs with different colors, such as LEDs for the three primary colors (red, green and blue, R/G/B), or LEDs for complementary colors (blue and yellow), are activated simultaneously.
  • LEDs for the three primary colors red, green and blue, R/G/B
  • LEDs for complementary colors blue and yellow
  • the blue phosphors used in white LEDs are important as they greatly affect the characteristics of light-emitting devices.
  • the difference between white LEDs and fluorescent lamps is that while the excitation wavelength of fluorescent lamps is 254 nm, the excitation wavelength of white LEDs lies at the longer wavelength of 380 nm.
  • the “BAM phosphor” mentioned above has been proposed for use as a blue phosphor used in white LEDs.
  • the excitation source differs depending on the phosphor application, so it is hoped that, with diversification of applications, phosphors characterized by strong light emissions across a wide excitation wavelength range will be developed.
  • BAM phosphors have been proposed for applications involving blue phosphors, which have a particularly strong effect on the characteristics of light-emitting devices.
  • BAM phosphors do not yet provide light emissions of satisfactory intensity and a higher level of luminous efficacy is desired.
  • BAM phosphors emit light of moderately adequate intensity at the fluorescent lamp excitation wavelength of 254 nm as noted above, when the excitation wavelength is shifted to the longer UV LED wavelength of 380 nm, the intensity of light emission is gradually reduced.
  • the objective of the present invention is to provide a novel phosphor capable of exhibiting strong light emissions over a wide excitation wavelength range, and a light-emitting device using such a phosphor. Also, the present invention provides a novel phosphor that exhibits stronger light emissions particularly under ultraviolet excitation than are obtained using a conventional BAM phosphor as the blue phosphor, and a light-emitting device using such a phosphor.
  • the present invention also provides a novel phosphor that is well-suited for use as a blue phosphor in products such as white LEDs and fluorescent lamps using UV as an excitation source, and a light-emitting device using such a phosphor.
  • the present invention further provides a novel phosphor that can be used as a blue phosphor in products such as PDPs having vacuum ultraviolet light as an excitation source, and a light-emitting device using such a phosphor.
  • the present invention was configured as follows to achieve the purposes cited above.
  • One aspect of the invention pertains to a phosphor characterized by the fact that it contains a metal oxide containing at least one alkaline earth element selected from the group composed of Ca, Sr, and Ba, at least one element selected from the group composed of Be, Cu, Zn, Pb, Cd, Mg, and Sn, at least one element selected from the group composed of B, Al, Ga, and In, and at least one element selected from the group composed of P and V, in which at least one element selected from the group composed of Ce, Pr, Sm, Nd, Gd, Eu, Tb, Dy, Ho, Tm, Er, Yb, and Mn is contained as an added activator.
  • Another aspect of the invention pertains to a phosphor characterized by the fact that it is represented by the following composition formula: ( a ⁇ x )M1O. b M2O. c M3O 1.5 .d M4O 2.5 :x LnO
  • M1 represents at least one alkaline earth element selected from the group composed of Ca, Sr, and Ba
  • M2 represents at least one element selected from the group composed of Be, Cu, Zn, Pb, Cd, Mg, and Sn
  • M3 represents at least one element selected from the group composed of B, Al, Ga
  • M4 represents at least one element selected from the group composed of P and V
  • Ln is at least one element selected from the group composed of Ce, Pr, Sm, Nd, Gd, Eu, Tb, Dy, Ho, Tm, Er, Yb, and Mn
  • the letters x, a, b, c, and d represent numbers that each satisfy the following conditions: 0 ⁇ x ⁇ 0.5, 1 ⁇ a ⁇ 3, 0 ⁇
  • Another aspect of the invention pertains to the phosphor related to the aspect of the invention described above, characterized by the fact that the ranges for b and c are 0 ⁇ b ⁇ 4 and 0 ⁇ c ⁇ 9.
  • Another aspect of the invention pertains to the phosphor related to one of the aspects of the invention described above, characterized by the fact that ultraviolet light or vacuum ultraviolet light is used as the excitation source.
  • Another aspect of the invention pertains to a light-emitting device characterized by the fact that it uses the phosphor related to one of the aspects of the invention described above.
  • Another aspect of the invention pertains to the light-emitting device related to the aspect of the invention described above, characterized by the fact that ultraviolet light or vacuum ultraviolet light is used as the excitation source.
  • ultraviolet light or vacuum ultraviolet light as used in the Claims and the Specification of this application is taken to include those situations involving either ultraviolet light or vacuum ultraviolet light, and also those situations involving both ultraviolet light and vacuum ultraviolet light.
  • FIG. 1 is a graph showing emission spectra for phosphor powder with ultraviolet excitation at a wavelength of 254 nm, as obtained in Working Examples 1 through 5 and Comparative Example 1.
  • FIG. 2 is a graph showing excitation spectra for phosphor powder as obtained in Working Examples 1 through 5 and Comparative Example 1.
  • the present invention is for a phosphor characterized by the fact that it contains a metal oxide containing at least one alkaline earth element selected from the group composed of Ca, Sr, and Ba, at least one element selected from the group composed of Be, Cu, Zn, Pb, Cd, Mg, and Sn, at least one element selected from the group composed of B, Al, Ga, and In, and at least one element selected from the group composed of P and V, in which at least one element selected from the group composed of Ce, Pr, Sm, Nd, Gd, Eu, Tb, Dy, Ho, Tm, Er, Yb, and Mn is contained as an added activator, with this phosphor preferably represented by the following composition formula. ( a ⁇ x )M1O.
  • M1 represents at least one alkaline earth element selected from the group composed of Ca, Sr, and Ba
  • M2 represents at least one element selected from the group composed of Be, Cu, Zn, Pb, Cd, Mg, and Sn
  • M3 represents at least one element selected from the group composed of B, Al, Ga, and In
  • M4 represents at least one element selected from the group composed of P and V.
  • Ln is at least one element selected from the group composed of Ce, Pr, Sm, Nd, Gd, Eu, Tb, Dy, Ho, Tm, Er, Yb, and Mn.
  • the letters x, a, b, c, and d represent numbers that each satisfy the following conditions: 0 ⁇ x ⁇ 0.5, 1 ⁇ a ⁇ 3, 0 ⁇ b ⁇ 4, 0 ⁇ c ⁇ 9, and 2 ⁇ d ⁇ 9.
  • Phosphors related to the present invention are manufactured by using, for example, the following phosphor raw materials.
  • M1 is at least one alkaline earth element selected from the group composed of Ca, Sr, and Ba.
  • M1 raw materials are oxides of M1 elements, and compounds of M1 elements such as carbonates, nitrates, sulfates, or halides of M1 elements that can easily be converted to oxides of M1 elements at high temperatures.
  • M2 is at least one element selected from the group composed of Be, Cu, Zn, Pb, Cd, Mg, and Sn.
  • M2 raw materials include oxides of M2 elements, and compounds of M2 elements such as carbonates, nitrates, sulfates, or halides of M2 elements that can easily be converted to oxides of M2 elements at high temperatures.
  • M3 is at least one element selected from the group composed of B, Al, Ga, and In.
  • M3 raw materials include oxides of M3 elements, and compounds of M3 elements such as carbonates, nitrates, sulfates, or halides of M3 elements that can easily be converted to oxides of M3 elements at high temperatures.
  • M4 is at least one element selected from the group composed of P and V.
  • M4 raw materials include oxides of M4 elements, and compounds of M4 elements such as carbonates, nitrates, sulfates, or halides of M4 elements that can easily be converted to oxides of M4 elements at high temperatures.
  • the added activator Ln is at least one element selected from the group composed of Ce, Pr, Sm, Nd, Gd, Eu, Tb, Dy, Ho, Tm, Er, Yb, and Mn.
  • Ln raw materials include oxides of Ln elements, and compounds of Ln elements such as carbonates, nitrates, sulfates, or halides of Ln elements that can easily be converted to oxides of Ln elements at high temperatures.
  • These raw materials are measured out in specific quantities and mixed together.
  • This mixing can be accomplished by publicly known methods, including for example wet mixing and dry mixing. Chemical reactions such as the sol-gel method and the coprecipitation method can also be used to prepare the raw materials.
  • this mixture of raw materials is dried, it is placed in a heat-resistant container such as an alumina crucible, and in inert gas, in a reducing atmosphere of hydrogen gas or the like, or in a reducing atmosphere containing water vapor, the mixture is baked at, for example, 800° C. to 1400° C. for 1 to 50 hours, to yield a phosphor of the present invention.
  • a heat-resistant container such as an alumina crucible
  • in inert gas in a reducing atmosphere of hydrogen gas or the like, or in a reducing atmosphere containing water vapor
  • the mixture is baked at, for example, 800° C. to 1400° C. for 1 to 50 hours, to yield a phosphor of the present invention.
  • the resulting phosphor can be crushed and rebaked repeatedly.
  • the product is powdered, washed with water, dried, and sifted as needed to prepare a phosphor of the targeted granularity.
  • excitation sources that can be used for the excitation of the phosphors of the present invention for light emission are electron beams, ultraviolet light, vacuum ultraviolet light obtained by discharging an electrical current within a noble gas, and X-rays.
  • a phosphor of the present invention emits a stronger light than the conventional blue BAM phosphor particularly under ultraviolet excitation.
  • the light-emitting devices of the present invention include, but are not limited to, for example, fluorescent lamps (low-pressure mercury lamps, high-pressure mercury lamps), white LEDs using ultraviolet LEDs, CRTs, noble gas lamps, PDPs, radiation-sensitized paper, and fluorescent plates. Since the phosphors of the present invention exhibit excellent light-emission intensities, particularly under ultraviolet excitation, they can be used suitably as white LEDs or fluorescent lamps utilizing ultraviolet light excitation. Additionally, they are useful in noble gas lamps or PDPs utilizing vacuum ultraviolet light excitation.
  • BAM phosphor europium-activated barium-magnesium-aluminum oxide phosphor
  • raw materials were each weighed out in the following quantities and mixed together: barium carbonate (BaCO 3 ) 2.32 g, magnesium hydroxide (Mg(OH) 2 ) 0.75 g, aluminum oxide (Al 2 O 3 ) 6.48 g, aluminum fluoride (AlF 3 ) 0.22 g, and europium oxide (Eu 2 O 3 ) 0.23 g.
  • barium carbonate BaCO 3
  • magnesium hydroxide Mg(OH) 2
  • Al 2 O 3 aluminum oxide
  • AlF 3 aluminum fluoride
  • Eu 2 O 3 europium oxide
  • This mixture was placed in an alumina crucible and introduced into an electric kiln. Then, in a nitrogen gas atmosphere containing 4 vol % hydrogen gas, the mixture was baked at 1500° C. for 5 hours, yielding the targeted BAM phosphor.
  • the luminescence characteristics of the phosphors from Working Examples 1 through 5 and Comparative Example 1 were evaluated using the methods described below.
  • a commercially available spectrofluorophotometer (FP-777W, JASCO Corporation) was used to measure each emitted spectrum at the ultraviolet wavelength of 254 nm.
  • FIG. 1 shows the light emission spectra of each of the phosphor powders obtained in Working Examples 1 through 5, and in Comparative Example 1, at the ultraviolet excitation wavelength of 254 nm.
  • the intensity of the light emitted as a result of UV excitation wavelength of 254 nm was arbitrarily designated as 100 for the BAM phosphor of Comparative Example 1, the intensity of emitted light for the phosphors from the working examples was excellent in that it was 137 for Working Example 1, 126 for Working Example 2, 141 for Working Example 3, 134 for Working Example 4, and 114 for Working Example 5.
  • FIG. 2 shows the excitation spectra for the phosphor powders obtained in Working Examples 1 through 5 and in Comparative Example 1. As is clear from FIG. 2 , the phosphors in Working Examples 1 through 5 provided superior relative luminous efficacy in comparison to the BAM phosphor used in Comparative Example 1 at all excitation wavelengths from 220 to 400 nm.
  • a particular disadvantage of the BAM phosphor of Comparative Example 1 is that although this phosphor produces moderately strong light emissions at the fluorescent lamp excitation wavelength of 254 nm, its light emission strength is gradually reduced when the excitation wavelength is shifted to longer wavelengths such as ultraviolet LED's 380 nm.
  • the phosphor of Working Example 1 shows an excellent relative luminous efficacy that is approximately 1.8 times that of the BAM phosphor at the longer wavelengths such as ultraviolet LED's 380 nm. Results were similarly excellent for the other Working Examples (relative luminous efficacy approximately 1.4 times that of the BAM phosphor in Working Example 2, approximately 1.7 times in Working Example 3, approximately 1.4 times in Working Example 4, and approximately 1.4 times in Working Example 5).
  • the present invention pertains to a light-emitting material capable of exhibiting strong light emissions over a wide excitation wavelength range.
  • a BAM phosphor which is a conventional blue phosphor.
  • it is well-suited for use as a blue phosphor in products such as white LEDs and fluorescent lamps using ultraviolet light as an excitation source, and can also be used as a blue phosphor in products such as PDPs using vacuum ultraviolet light as an excitation source.
  • Use of the phosphor of the present invention makes it possible to provide excellent light-emitting devices.

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  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Luminescent Compositions (AREA)
  • Gas-Filled Discharge Tubes (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Led Device Packages (AREA)
US11/570,814 2004-06-18 2005-05-27 Phosphor and Light-Emitting Device Using Same Abandoned US20070224076A1 (en)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
JP2004-181765 2004-06-18
JP2004181765 2004-06-18
JP2005107874A JP3754701B2 (ja) 2004-06-18 2005-04-04 蛍光体及びそれを使用した発光素子
JP2005-107874 2005-04-04
PCT/JP2005/009763 WO2005123877A1 (ja) 2004-06-18 2005-05-27 蛍光体及びそれを使用した発光素子

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US (1) US20070224076A1 (de)
EP (1) EP1783192B1 (de)
JP (1) JP3754701B2 (de)
AT (1) ATE550406T1 (de)
WO (1) WO2005123877A1 (de)

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Publication number Priority date Publication date Assignee Title
EP1865044B1 (de) 2005-03-29 2009-11-18 Nemoto & Co., Ltd. Infrarotes licht emittierende fluoreszierende substanz
CN104592992B (zh) * 2015-02-04 2016-06-01 嘉兴学院 一种紫光led激发的蓝色荧光粉及其制备方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3647708A (en) * 1969-07-29 1972-03-07 Philips Corp Luminescent material
US4353808A (en) * 1979-03-30 1982-10-12 Hitachi, Ltd. Phosphors and process for producing the same
US20050035331A1 (en) * 2003-06-24 2005-02-17 Xiao-Dong Sun Phosphorescent blends
US20050145854A1 (en) * 2002-02-15 2005-07-07 Mitsubishi Chemical Corporation Light emitting device and illuminator using the same

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JPS5354184A (en) * 1976-10-28 1978-05-17 Dainippon Toryo Co Ltd Fluorescent substance and fluorescent lamp
JPS5947288A (ja) * 1982-09-10 1984-03-16 Toshiba Corp 螢光体
JPS61246283A (ja) * 1985-04-24 1986-11-01 Matsushita Electronics Corp 螢光体
JPH02187490A (ja) * 1989-01-13 1990-07-23 Hitachi Ltd 蛍光体組成物
JP2843648B2 (ja) * 1990-06-08 1999-01-06 日亜化学工業株式会社 青色発光蛍光体
JPH09111235A (ja) * 1995-10-17 1997-04-28 Toshiba Corp 蛍光体および蛍光ランプ
JPH09286983A (ja) * 1996-04-22 1997-11-04 Matsushita Electron Corp 蛍光体
US6522065B1 (en) * 2000-03-27 2003-02-18 General Electric Company Single phosphor for creating white light with high luminosity and high CRI in a UV led device
JP5157029B2 (ja) * 2001-05-31 2013-03-06 日亜化学工業株式会社 蛍光体を用いた発光装置
JP2003313551A (ja) * 2002-02-22 2003-11-06 Sumitomo Chem Co Ltd 真空紫外線励起発光素子用の蛍光体
JP4337465B2 (ja) * 2003-08-08 2009-09-30 三菱化学株式会社 発光装置及び照明装置ならびに画像表示装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3647708A (en) * 1969-07-29 1972-03-07 Philips Corp Luminescent material
US4353808A (en) * 1979-03-30 1982-10-12 Hitachi, Ltd. Phosphors and process for producing the same
US20050145854A1 (en) * 2002-02-15 2005-07-07 Mitsubishi Chemical Corporation Light emitting device and illuminator using the same
US20050035331A1 (en) * 2003-06-24 2005-02-17 Xiao-Dong Sun Phosphorescent blends

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JP2006028480A (ja) 2006-02-02
ATE550406T1 (de) 2012-04-15
JP3754701B2 (ja) 2006-03-15
WO2005123877A1 (ja) 2005-12-29
EP1783192A4 (de) 2009-11-11
EP1783192B1 (de) 2012-03-21
EP1783192A1 (de) 2007-05-09

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