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:
Nov. 20, 2007
Filed:
Mar. 17, 2003
Shiro Iida, Kyoto, JP;
Akiko Nakanishi, Hirakata, JP;
Shiro Iida, Kyoto, JP;
Akiko Nakanishi, Hirakata, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
This invention aims at providing a low-pressure mercury lamp having an improved luminous efficiency while maintaining the compactness and long life of the arc tube. This lamp comprises an arc tube formed by bending a glass tube. This arc tube is formed into a double-spiral structure comprising: a turning part located in substantially the midsection from both ends of the glass tube; a first spiral part starting from one of the ends and spiraling around the pivotal axis to reach the turning part; and a second spiral part starting from the turning part and spiraling around the pivotal axis to the other end. The glass tube has a circular shape in cross section with 7.4 mm inner diameter. This low-pressure mercury lamp is a 12 W lamp alternative to a 60 W incandescent lamp, and the bulb wall loading under steady state illumination is set at 0.103 W/cm.