White light source including LED and phosphors
AssigneesKabushiki Kaisha Toshiba, Toshiba Materials Co., Ltd.
InventorsTatsunori Itoga, Ryoji Tsuda, Naotoshi Matsuda, Yoshitaka Funayama
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Abstract
According to one embodiment, a white light source includes a combination of a light emitting diode and phosphors. One of the phosphors is at least a cerium activated yttrium aluminum garnet-based phosphor. There is no light emission spectrum peak at which a ratio of a largest maximum value to a minimum value is greater than 1.9. The largest maximum value is largest among at least one maximum value present in a wavelength range of 400 nm to 500 nm in a light emission spectrum of white light emitted from the white light source. The minimum value is adjacent to the largest maximum value in a longer wavelength side of the light emission spectrum.
Claims12
A white light source comprising:
- a light emitting diode (LED);
- and
- phosphors,
- wherein one of the phosphors is at least a cerium activated yttrium aluminum garnet-based phosphor,
- wherein there is no light emission spectrum peak that has a ratio of a largest maximum value to a minimum value of greater than 1.9,
- wherein the ratio is defined by a light emission spectrum intensity in a wavelength that indicates the largest maximum value divided by a light emission spectrum intensity in a wavelength that indicates the minimum value,
- wherein the largest maximum value is a largest value among at least one maximum light emission intensity value present in a wavelength range of 400 nm to 500 nm in a light emission spectrum of white light emitted from the white light source,
- wherein the minimum value is a light emission intensity value having a minimum value and being adjacent to the largest maximum value in a longer wavelength side of the light emission spectrum, and
- wherein an average color rendering index Ra of white light emitted from the white light source is 96 or higher, and wherein all color rendering indices R1 to R15 are 85 or higher.
Dependencies are inferred from the claim text.