© General Electric
George E. Inman and Richard N. Thayer, 1936
demonstrating a fluorescent lamp.
one time in development, rival cathode designs from the Inman and
Pritchard groups necessitated the intervention of a neutral physicist
from GE's Research Lab., who ruled in favor of the Pritchard design."
-- Richard N. Thayer, in an unpublished paper, 1989
inventors, including Thomas Edison, explored the use of fluorescent
materials in electric lamps during the late 19th and early 20th
centuries. Results were not promising. As other designs matured and the
tungsten-filament incandescent lamp came to dominate the market,
research into fluorescent lamps stayed at a low level. Some researchers
doubted that a practical lamp could be made. As co-inventor Richard
Thayer recounted years later:
||"Imagine our surprise when we
received a report in August 1934 that the laboratory of the General
Electric Co. Ltd. in London (no relation to U.S. GE) had made
experimental green fluorescent lamps with an efficiency of 35 lumens
per watt -- three times that of household-sized incandescent lamps! We
thought that the decimal point must be wrong, and that the correct
figure was 3.5 lpw. But further European information was confirming,
and in December 1934 we began U.S. development."
Inman headed a group at GE's Nela Park facility (in Cleveland) that
began looking into fluorescent lamp development. To save time, he
adopted the design of an existing tubular incandescent lamp in order to
make use of available production equipment and lamp parts. Speed was
important. Not only were European competitors already working, but
American companies Westinghouse and Sylvania were also beginning to
look at fluorescents.
second GE group was set up under Philip J. Pritchard "to adapt,
develop, and build automatic equipment to manufacture the lamp."
Different opinions about various technical details like cathode design
caused friction between the rival teams, as Thayer noted above. Also,
fluorescent lamps were more complicated devices than simple
incandescent lamps. This meant that other GE groups (in Schenectady and
in Ft. Wayne) assisted in developing ballasts and resolving problems of
1938, GE began offering fluorescent tubes for sale -- in four sizes.
One size from each of the two Nela Park teams, one compromise between
those two, and one especially for industrial use. However, the size
that ultimately sold best (48 inches, 40 watt) was not introduced until
a year later as, "it seemed to us then an impractically large lamp."