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US 8,796,915 B2Granted
LED light bulb
AssigneesKabushiki Kaisha Toshiba, Toshiba Materials Co., Ltd.
InventorsYasumasa Ooya, Masahiko Yamakawa, Yasuhiro Shirakawa, Katsutoshi Nakagawa
Life of this patent
Estimating the term…
Abstract
In one embodiment, an LED light bulb includes an LED module, a base part on which the LED module is disposed, and a globe attached to the base part. The LED module includes an ultraviolet to violet light-emitting LED chip mounted on a substrate. A lighting circuit and a bayonet cap are provided at the base part. A phosphor screen emitting white light by absorbing the ultraviolet to violet light emitted from the LED chip is provided on an inner surface of the globe. The phosphor screen has a color in which a* is −10 or more and +10 or less, b* is 0 (zero) or more and +30 or less, and L* is +40 or more when a body color thereof is represented by an L*a*b* color system.
Claims12
An LED light bulb, comprising:
- an LED module including a substrate and an ultraviolet to violet light-emitting LED chip mounted on the substrate;
- a base part on which the LED module is disposed;
- a globe attached to the base part to cover the LED module;
- a phosphor screen, provided on an inner surface of the globe separately from the LED chip, emitting white light by absorbing ultraviolet to violet light emitted from the LED chip;
- a lighting circuit, provided in the base part, lighting the LED chip;
- and
- a bayonet cap electrically connected to the lighting circuit,
- wherein the phosphor screen includes a mixed phosphor containing a blue phosphor, a green to yellow phosphor, and a red phosphor,
- wherein the blue phosphor comprises an europium activated alkaline earth chlorophosphate phosphor having a composition represented by a general formula:
- (Sr1-x-y-zBaxCayEuz)5(PO4)3.Cl (1)
- where, x, y, and z are numbers satisfying 0≦x<0.5, 0≦y<0.1, 0.0005≦z<0.1,
- wherein the green to yellow phosphor comprises at least one selected from:
- an europium and manganese activated alkaline earth aluminate phosphor having a composition represented by a general formula:
- (Ba1-x-y-zSrxCayEuz)(Mg1-uMnu)Al10O17 (2)
- where, x, y, z, and u are numbers satisfying 0≦x<0.2, 0≦y<0.1, 0.005<z<0.5, 0.1<u<0.5;
- an europium and manganese activated alkaline earth silicate phosphor having a composition represented by a general formula:
- (Sr1-x-y-z-uBaxMgyEuzMnu)2SiO4 (3)
- where, x, y, z, and u are numbers satisfying 0.1≦x≦0.35, 0.025≦y≦0.105, 0.025≦z≦0.25, 0.0005≦u≦0.02;
- a cerium activated rare-earth aluminate phosphor having a composition represented by a general formula:
- RE3AxAl5-x-yByO12:Cez (4)
- where, RE is at least one element selected from Y, Lu, and Gd, A and B are a pair of elements where (A, B) is an of (Mg, Si), (B, Sc), (B, In), and x, y, and z are numbers satisfying x<2, y<2, 0.9<x/y≦1.1, 0.05≦z≦0.5;
- an europium activated SiAlON phosphor having a composition represented by a general formula:
- (Si,Al)6(O,N)8:Eux (5)
- where, x is a number satisfying 0<x<0.3;
- and
- an europium activated SiAlON phosphor having a composition represented by a general formula:
- (Sr1-xEux)αSiβAlγOδNω (6)
- where, x, α, β, γ, δ, and ω are numbers satisfying 0<x<1, 0<≦3, 12≦β≦14, 2≦γ≦3.5, 1≦δ≦3, 20≦ω≦22,
- wherein the red phosphor comprises at least one selected from:
- an europium activated lanthanum oxysulfide phosphor having a composition represented by a general formula:
- (La1-x-yEuxMy)2O2S (7)
- where, M is at least one element selected from Sm, Ga, Sb, and Sn, and x and y are numbers satisfying 0.08≦0.16, 0.000001≦y<0.003;
- an europium activated yttrium oxide phosphor having a composition represented by a general formula:
- (Y1-x-yEuxBiy)2O3 (8)
- where, x and y are numbers satisfying 0.01≦x<0.15, 0.001≦y<0.05;
- an europium activated CASN phosphor having a composition represented by a general formula:
- (Ca1-x-ySrxEuy)SiAlN3 (9)
- where, x and y are numbers satisfying 0≦x<0.4, 0<y<0.5;
- and
- an europium activated SiAlON phosphor having a composition represented by a general formula:
- (Sr1-xEux)αSiβAlγOδNω (10)
- where, x, α, β, γ, δ, and ω are numbers satisfying 0<x<1, 0<α≦3, 5≦β≦9, 1≦γ≦5, 0.5≦δ≦2, 5≦ω≦15,
- wherein a total content of the europium and manganese activated alkaline earth silicate phosphor having the composition represented by the formula (3), the cerium activated rare-earth aluminate phosphor having the composition represented by the formula (4), the europium activated SiAlON phosphor having the composition represented by the formula (5), the europium activated SiAlON phosphor having the composition represented by the formula (6), the europium activated CASN phosphor having the composition represented by the formula (9), and the europium activated SiAlON phosphor having the composition represented by the formula (10) in the mixed phosphor is 20 mass % or less, and
- wherein the phosphor screen has a color in which a* is −10 or more and +10 or less, b* is 0 (zero) or more and +30 or less, and L* is +40 or more when a body color of the phosphor screen is represented by an L*a*b* color system.
41 more elements
Dependencies are inferred from the claim text.