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. 16, 1993
Filed:
Feb. 28, 1992
Tadashi Yano, Osaka, JP;
Kenjiro Hashimoto, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
Provided is an illumination device in which natural light having a correlated color temperature equivalent to that of artificial light can be obtained so that there is no feeling of physical disorder against the artificial light when the natural light is used in combination with the artificial light for energy saving. In the illumination device, luminous flux of natural light in a visible light range (380 nm-780 nm) is detected by a color temperature sensor in a first light detector portion (8), the correlated color temperature of the natural light is obtained through operation by a first operation portion (9), artificial light is detected by a color temperature sensor in a second light detector portion (10), the correlated color temperature of the artificial light is obtained through operation by a second operation portion (11), and color temperature converting filters are switched by a filter operating portion (14) so that a difference between the correlated color temperature of the natural light and the correlated color temperature of the artificial light obtained through operation by a third operation portion is made equal to or smaller than 5.5 mired to thereby obtain mixed light giving no feeling of physical disorder.