4.4 Detailed patent study of a fluorescent tube lamp
Having compiled the patent profile of fluorescent tube lighting, the authors wanted to get an
insight into the type of contradictions solved in environmentally relevant patents. To do this,
such patents would need to be studied in more detail. This section reports on the first of
these more detailed patent studies.
The patent chosen from the patent profile fluorescent tube lighting was US5898265: Toxic
Characteristic Leaching Procedure (TCLP) compliant fluorescent lamp. The TCLP test is a
toxicity test established in 1990 by EPA to prevent large quantities of heavy metal going to
landfill. The patent records a combination of innovations that lead to environmental (TCLP)
compliance for a fluorescent tube lamp, and must therefore contain environmentally
relevant innovations. The patent describes the reduction of the total mercury content by
more than 80% (factor 4) whilst providing a lamp-life and photometric quality comparable to
other commercially available fluorescent lamps. These lamps no longer pose danger in
landfill and can be safely disposed of in landfill whilst also still being 100% recyclable, a
more expensive disposal option. Competitors’ lamps often use mercury-binding agents that
‘cheat’ the TCLP test.
Press releases from the patent owners (Philips, [http://www.eur.lighting.philips.com], 2000)
and product brochures of the fluorescent tube lamps ‘Alto’ and ‘TL’D Super 80’
supplemented the information contained in the patent. These helped the authors
understand the environmental benefits of the innovations described in the patent.