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:
Oct. 28, 2003
Filed:
Jun. 13, 2001
Erik Paul Boonekamp, Eindhoven, NL;
Johannes Adrianus Frederikus Peek, Leves, FR;
Wolfgang Doetter, Aachen, DE;
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
The electric lamp employs a lamp vessel ( ), which is transparent to visible light and which accommodates a light source ( ). The lamp vessel ( ) is covered with a combination of a light-absorbing medium ( ) and an optical interference film ( ) employing layers of alternately a first layer of a material with a comparatively high refractive index and a second layer of silicon dioxide. A spectral transmission T of light transmitted by the light-absorbing medium ( ) changes from T≦0.15 to T≧0.75 in a wavelength range having a width &lgr;≦50 nm. The variation in reflection R amounts to less than 10% in the wavelength range 400≦R≦690 nm, the reflection R and lies in the range 50≦R≦90%. In operation, the electric lamp emits colored light in the transmission mode and has a substantially color-neutral appearance in the off state.