Low-pressure sodium lamp
Lámpara de vapor de sodio de baja presión
- Date
- c. 1932 · confidence medium
- Place
- Eindhoven, North Brabant, Netherlands
- Credited to
- Philips (Netherlands)
- Field
- Matter & energy
⚠️ Disputed: the sources disagree.
What it is
A discharge lamp whose sodium vapour emits almost all its light in a single, very efficient yellow line. It took over road, tunnel and port lighting for its efficiency, though it hardly renders colours.
Sodium lamps were being tried from the 1920s (Compton, Westinghouse); the commercial launch in 1932 was Philips', with GE almost at the same time. The date is approximate.
What it led to
- public lighting of roads and motorways
- less light pollution near observatories (monochromatic light)
- high-pressure sodium lamps