The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 28, 2017
Filed:
Oct. 19, 2012
Kabushiki Kaisha Toshiba, Tokyo, JP;
Toshiba Materials Co., Ltd., Yokohama-shi, Kanagawa-ken, JP;
Masahiko Yamakawa, Yokohama, JP;
Yasuhiro Shirakawa, Yokohama, JP;
KABUSHIKI KAISHA TOSHIBA, Tokyo, JP;
TOSHIBA MATERIALS CO., LTD., Yokohama-Shi, JP;
Abstract
The present invention provides a white light source comprising a light emitting diode having a light emission peak wavelength of 350 to 490 nm and a phosphor that emits visible light upon excitation by a light emitted from the light emitting diode; wherein, with respect to an arbitrary local maximum value of light-emission intensity between 350 and 780 nm of a light emission spectrum of the white light source, a ratio of a local minimum value of light-emission intensity that is closest on a long wavelength side to the local maximum value is such that, when the local maximum value is taken as 1, the local minimum value is 0.5 or more. It is preferable that, with respect to an arbitrary local maximum value of light-emission intensity between 350 and 780 nm of a light emission spectrum of the white light source, a ratio of a local minimum value of light-emission intensity that is closest on a long wavelength side to the local maximum value is such that, when the local maximum value is taken as 1, the local minimum value is 0.7 or more. According to the above structure, there can be provided a white light source capable of preventing a specified wavelength region from protruding in the light emission spectrum, and capable of visually perceiving the color tone of the irradiation object as the same state where the object is irradiated with sunlight.