I have just finished my new book “Eureka!”. It is all about those
dramatic moments in history when a new product or process was first discovered
(if you want a copy please email me at VernonStent@hotmail.com) . One of the inventions that did not make
it into the book was the fluorescent lamp (or tube). That is not to say it isn’t
a fascinating story – it certainly is. The trouble is that there is not one big
“eureka” moment. It could be said that the fluorescent lamp was never
really invented at all but that it evolved over time.
The creation of the fluorescent lamp was a truly joint effort spanning a
century: Here are the milestones:
1675: Jean Picard, a French astronomer, noted that mercury in a barometer
tube would glow when shaken. He recorded this observation but did not understand
1846: Julius Plücker, German mathematician and physicist, theorized and
experimented with coloured light produced by passing electricity through various
gasses. He worked with glassblower Heinrich Geissler who invented what was to
become known as the Geissler tube in which the experiments were conducted.
1850’s: Heinrich Geissler continued to develop light emitting tubes
1857: Frenchman Alexandre Edmond Becquerel experimented with electric
discharge tubes coated on the inside with various luminescent materials
1868: Becquerel published his landmark treatise La Lumiere, ses causes et ses effets
1893 Nikola Tesla, originally from Serbia, developed the fluorescent light
using high frequency lighting ballasts
1894 Daniel McFarlane Moore, a U.S. inventor created the gas discharge lamp
using carbon dioxide and nitrogen to produce white and pink light respectively
1901: Serial inventor Peter Cooper Hewitt from New York, invented the mercury
vapour lamp. For the first time fluorescent lamps were being produced
commercially, albeit on a small scale
1926: Edmund Germer, Friedrich Meyer and Hans J. Spanner – all from Germany –
managed to produce a fluorescent tube with greater gas pressure and a fluorescent
inner coating that converted ultra violet light into visible white light.
1938: Having purchased the patent from Edmund Germer, General Electric mass
produced fluorescent lamps.
1974: GE Lighting invented the energy-efficient compact fluorescent bulb
How Does it Work?
First you need a glass tube that has small amount of a certain gas and some
mercury sealed inside – and nothing else. The gas will be argon or neon or any
of a number of other gasses (each produces its own unique colour). Electricity
is passed from one end of the tube to another. The electrons that pass through
ionise the atoms in the mixture and cause it to emit ultra violet light. The
electricity output must be limited before it can pass through, using a choke or
ballast. Without this limiting factor, fluorescent tubes could explode! By
contrast, a high voltage is required to get the whole process started. When the
lamp is first switched on, a starter is used to provide this
“kick-start”. The starter may be an integral part of the lamp build
and may be automatic or it may be a separate unit, typically a small plug that
twists into position.
The fluorescent lamp has had quite a journey from Jean Picard’s early musings
to the energy-efficient lamps of today. They are used in may applications. One
of these applications is the fly killer machine. Insectocutor fly killers use
ultra violet fluorescent tubes that attract flies in order to trap and kill
them. Each uv bulb comes complete with a starter and a choke.