White lights, big city

PUBLISHED : Tuesday, 12 July, 2005, 12:00am
UPDATED : Tuesday, 12 July, 2005, 12:00am

White led

Colour LEDs are easy to manufacture, but white LEDs are tougher to make. White light is produced by adding phosphor to a blue LED.


Backers of the technology envision white LEDs replacing tungsten lighting in the home. Because of high manufacturing costs, this could take several years.


The initial market for LED lighting has been in the transport sector. LEDs last as long as 100,000 hours, compared with 5,000 for normal lighting, thus reducing maintenance costs.


Another market for LEDs is outdoor signage, such as this Philips display. LED lighting uses less energy, cutting electricity costs for advertisers.