Lightbulb shapes and history questions

[shaunnie]

Hello,

I am a toy design student at the Fashion Institute of Technology of the State University of NY. I'm writing a paper for a history of industrial design class on lightbulbs.

I was wondering if there was a particular reason for globe-like shape of the conventional light bulb.

Additonally, does anyone know anything about how popular early lightbulbs were within homes?

I would also be very grateful if someone could point me to some resources regarding the manufacturing processes of lightbulbs.

Thanks!

[adam2]

Light bulbs are made in many shapes, but basic physics places certain limits on what shapes can be chosen.

Most early lamp types contain a vacuum, therefore the air imposes considerable stress on the glass bulb, which must be a suitable shape so as not to shatter.
A sphere would be the strongest, but has the disadvantage that the cap is very close to the filament, which except in very low power lamps, would result in the cap and lampholder becoming too hot.

Later lamp types are often gas filled, but similar constraints apply, since when cold the lamp will be below atmospheric pressure, and when hot above.

Very small lamps can be made in almost any shape, look at shaped Christmas bulbs for example, but larger ones can only be readily made in sphereical, pear shaped or tubular styles.
Odd shaped lamps can be made but tend to be expensive, or less efficient, or liable to shatter.

[Chris Kocsis]

Regarding the history of the bulb-making process, there is probably some information on-line but a good general treatment can be found in one of the volumes of the Oxford history of technology.  Two other books you should see are The History of the Incandescent Lamp by Howell and Schroeder, and Lamps for a Brighter America by John F. Keating.  They both concentrate mostly on the evolution of the Edison/General Electric line but that history includes most of the development of the ordinary tungsten-filament household bulbs.  For deeper insight into the commercial history from a business standpoint from early times to about 1940, see Arthur Bright's The Electric Lamp Industry.  Come back with questions as they occur to you -- good luck with your project!