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US 8,426,882 B2Granted
White light-emitting lamp for illumination and illuminating device using the same
AssigneesKabushiki Kaisha Toshiba, Toshiba Materials Co., Ltd.
InventorsRyo Sakai, Tsutomu Ishii, Yasuhiro Shirakawa, Masahiko Yamakawa, Yumi Ito
Life of this patent
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Abstract
A white light emitting lamp 1 includes a phosphor layer 5 which emits white light by being excited by light emitted from a semiconductor light emitting element 2. A transparent resin layer 4 is interposed between the semiconductor light emitting element 2 and the phosphor layer 5. The phosphor layer 5 contains, as a green phosphor, a rare earth borate phosphor activated by trivalent cerium and terbium.
Claims15
A white light emitting lamp for illumination, comprising:
- a semiconductor light emitting element which emits ultraviolet or violet light having a peak wavelength in a range of not less than 300 nm nor more than 430 nm;
- a transparent resin layer disposed to cover at least a light emitting surface of the semiconductor light emitting element;
- and
- a phosphor layer, disposed on the transparent resin layer, emitting white light by being excited by the ultraviolet or violet light emitted from the semiconductor light emitting element,
- wherein the transparent resin layer is provided between the semiconductor light emitting element and the phosphor layer, and has a thickness from the light emitting surface of the semiconductor light emitting element to the phosphor layer in a range of not less than 0.4 mm nor more than 10 mm,
- wherein the phosphor layer includes a green phosphor emitting green light by absorbing the ultraviolet or violet light, a blue phosphor emitting blue light by absorbing the ultraviolet or violet light, and a red phosphor emitting red light by absorbing the ultraviolet or violet light, and the transparent resin layer does not include the green, blue, and red phosphors, and
- wherein the green phosphor comprises a rare earth borate phosphor activated by trivalent cerium and terbium having a composition represented by a general formula:
- (R1-x-y)CexTbyBO3
- where, R represents at least one element selected from Sc, Y, La, Gd and Lu, and x and y are numbers satisfying 0.03<x<0.3 and 0.03<y<0.3.
6 more elements
Dependencies are inferred from the claim text.