LED light bulb

• US 8,955,996 B2
• Filed: 12/11/2012
• Issued: 02/17/2015
• Est. Priority Date: 06/28/2010
• Status: Active Grant

• Current Assignee: Seoul Semiconductor Co., Ltd.
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Materials Company Limited (Toshiba Corporation)
• Inventors: Ooya, Yasumasa, Yamakawa, Masahiko, Shirakawa, Yasuhiro, Nakagawa, Katsutoshi
• Primary Examiner(s): Hollweg, Thomas A
• Application Number:
  US13/711,000
• Publication Number:
  US 20130100645A1
• Time in Patent Office: 798 Days
• Field of Search: 313/498, 313501-603, 362/84, 362/260
• US Class Current: 362/84
• CPC Class Codes: C09K 11/663 with alkaline earth metals
• CPC Class Codes: C09K 11/7734 Aluminates
• CPC Class Codes: C09K 11/77342 Silicates
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: C09K 11/7739 with halogens
• CPC Class Codes: C09K 11/7789 Oxysulfides
• CPC Class Codes: F21K 9/232 specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21V 3/06 characterised by the material
• CPC Class Codes: F21V 9/06 for filtering out ultraviolet radiation
• CPC Class Codes: F21V 9/38 Combination of two or more photoluminescent elements of different materials
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

In one embodiment, an LED light bulb includes an LED module, a base portion on which the LED module is disposed, and a globe attached to the base portion. 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 in and on the base portion. A fluorescent film is provided on an inner surface of the globe, and emits white light by absorbing ultraviolet to violet light emitted from the LED chip. The fluorescent film has a film thickness in a range of 80 to 800 μm. In the LED light bulb, an amount of ultraviolet light which leaks from the globe is 0.1 mW/nm/lm or less.

Claims

1. 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 portion on which the LED module is disposed;

a globe attached to the base portion to cover the LED module;

a fluorescent film, 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 portion, lighting the LED chip; and

a bayonet cap electrically connected to the lighting circuit,

wherein the fluorescent film is made of a mixture of phosphor articles having a mean particle diameter of from 3 to 50 μ

m and a silicone resin as a binder, and has a film thickness in a range of from 80 to 800 μ

m,

wherein an amount of ultraviolet light which leaks from the globe is 0.1 mW/nm/lm or less, and

wherein a brightness of the LED light bulb is 35 lm/W or more.

2. The LED light bulb according to claim 1,

wherein the fluorescent film has the film thickness in a range of not less than 150 μ

m nor more than 600 μ

m.

3. The LED light bulb according to claim 1,

wherein the fluorescent film contains a blue phosphor, a green to yellow phosphor, and a red phosphor.

4. The LED light bulb according to claim 3,

wherein the blue phosphor includes a europium-activated alkaline earth chlorophosphate phosphor having a composition represented by a general formula:

(Sr_1-x-y-zBa_xCa_yEu_z)₅(PO₄)₃.Cl

where, a, x, y, and z are numbers satisfying 0≦

x<

0.5, 0≦

y<

0.1, and 0.005≦

z<

0.1),

wherein the green to yellow phosphor includes at least one selected from a europium and manganese-activated alkaline earth aluminate phosphor having a composition represented by a general formula;

(Ba_1-x-y-zSr_xCa_yEu_z)(Mg_1-uMn_u)Al₁₀O₁₇

where, x, y, z, and u are numbers satisfying 0≦

x<

0.2, 0≦

y<

0.1, 0.005<

z<

0.5, and 0.1≦

u≦

0.5;

a europium and manganese-activated alkaline earth silicate phosphor having a composition represented by a general formula;

(Sr_1-x-y-z-uBa_xMg_yEu_zMn_u)₂SiO₄

where, x, y, z, and u are numbers satisfying 0.1≦

x≦

0.35, 0.025≦

y≦

0.105, 0.025≦

z≦

0.25, and 0.0005≦

u≦

0.02;

a europium-activated sialon phosphor having a composition represented by a general formula;

(Si,Al)₆(O,N)₈;

Eu_x

where, x is a number satisfying 0≦

x≦

0.3; and

a europium-activated sialon phosphor having a composition represented by a general formula;

(Sr_1-xEu_x)_α

Si_β

Al_γ

O_δ

N_ω

where, x, α

, β

, γ

, δ

, and ω

are numbers satisfying 0≦

x≦

1, 0≦

α

≦

3, 12≦

β

≦

14, 2≦

γ

≦

3.5, 1≦

δ

≦

3, and 20≦

ω

≦

22, and

wherein the red phosphor includes at least one selected from a europium-activated lanthanum oxysulfide phosphor having a composition represented by a general formula;

(La_1-x-yEu_xM_y)₂O₂S

where, M is at least one element selected from Sm, Ga, Sb, and Sn, and x and y are numbers satisfying 0.08≦

x<

0.16 and 0.000001≦

y<

0.003;

a europium-activated CASH phosphor having a composition represented by a general formula;

(Ca_1-x-ySr_xEu_y)SiAlN₃

where, x and y are numbers satisfying and 0≦

x<

0.4 and 0<

y<

0.5; and

a europium-activated sialon phosphor having a composition represented by a general formula;

(Sr_1-xEu_x)_α

Si_β

Al_γ

O_δ

N_ω

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, and 5≦

ω

≦

15.

5. The LED light bulb according to claim 3,

wherein the fluorescent film contains, in a mass proportion, the blue phosphor in a range of not less than 10% nor more than 60%, the green to yellow phosphor in a range of not less than 1% nor more than 30% and the red phosphor in a range of not less than 30% nor more than 90%, and a total amount of the blue phosphor, the green to yellow phosphor and the red phosphor is 100%.

6. The LED light bulb according to claim 3,

wherein the fluorescent film further contains at least one phosphor selected from a blue-green phosphor and a deep red phosphor.

7. The LED light bulb according to claim 6,

wherein the blue-green phosphor includes a europium and manganese-activated alkaline earth silicate phosphor having a composition represented by a general formula:

(Ba_1-x-y-z-uSr_xMg_yEu_zMn_u)₂SiO₄

where, x, y, z, and u are numbers satisfying 0.1≦

x≦

0.35, 0.025≦

y≦

0.105, 0.025≦

z≦

0.25, and 0.0005≦

u≦

0.02, and

wherein the deep red phosphor includes a manganese-activated magnesium fluorogermanate phosphor having a composition represented by a general formula;

α

MgO.β

MgF₂.(Ge_1-xMn_x)O₂

where, α

, β

, and x are numbers satisfying 3.0≦

α

≦

4.0, 0.4≦

β

≦

0.6, and 0.001≦

x≦

0.5.

8. The LED light bulb according to claim 6,

wherein the fluorescent film contains, in a mass proportion, the blue phosphor in a range of not less than 10% nor more than 60%, the blue-green phosphor in a range of not more than 10%, the green to yellow phosphor in a range of not less than 1% nor more than 30%, the red phosphor in a range of not less than 30% nor more than 90% and the deep red phosphor in a range of not more than 35%, and a total amount of the blue phosphor, the blue-green phosphor, the green to yellow phosphor, the red phosphor and the deep red phosphor is 100%.

9. The LED light bulb according to claim 1,

wherein the globe is made of a translucent member having a light transmittance of 80% or more.

10. The LED light bulb according to claim 1,

wherein the ultraviolet to violet light emitted from the LED chip has an emission peak wavelength in a range of not less than 370 nm nor more than 410 nm, and has a full width at half maximum of an emission spectrum in a range of not less than 10 nm nor more than 15 nm.

11. The LED light bulb according to claim 1,

wherein the white light emitted from the fluorescent film has a correlated color temperature of 6500 K or less, and has an average color rendering index (Ra) of 85 or more.

12. The LED light bulb according to claim 1,

wherein the LED module includes a plurality of the LED chips surface-mounted on the substrate and a transparent resin layer provided on the substrate to cover the plurality of LED chips.

13. The LED light bulb according to claim 1,

wherein the globe has a dome shape or an eggplant shape.