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:
May. 27, 2003
Filed:
Sep. 27, 2000
Erik Paul Boonekamp, Eindhoven, NL;
Mathias Hubertus Johannes Van Rijswick, Eindhoven, NL;
Hendrik Adrianus Van Sprang, Eindhoven, NL;
Gerhard Hebbinghaus, Aachen, DE;
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
The electric lamp comprises a lamp vessel ( ) which transmits visible light and which accommodates a light source ( ). The electric lamp comprises a light-absorbing medium ( ). The lamp vessel ( ) is covered with an optical interference film ( ) which comprises layers composed of a first layer of silica and a second layer of a material having a relatively high refractive index which alternate with each other. According to the invention, light from the light source ( ) travels through the light-absorbing medium ( ) before reaching the interference film ( ). Preferably, the light-absorbing layer ( ) is disposed between the lamp vessel ( ) and the interference film ( ). Alternatively, the light-absorbing layer is contained in a wall of the lamp vessel. Preferably, the interference film ( ) reflects substantially in the same wavelength range as that wherein the light-absorbing medium ( ) absorbs, preferably in the range from 570 to 620 nm. Preferably, the electric lamp emits, in operation, colored light but has a color-neutral appearance when the lamp is in the off-state. The light-absorbing layer ( ) preferably predominantly comprises Nd O , CoAl O , Fe O , ZnFe O , ZnO.Fe O or BiVO .