Overview
A cold cathode fluorescent lamp (CCFL) is a lighting system that uses two phenomena: electron discharge and fluorescence. CCFLs are mainly used as light sources for backlights, because they are smaller and have longer lifetimes than ordinary fluorescent lamps. A wide range of brightness and color (color temperature and chromaticity) can be achieved by varying the type and pressure of the material injected into the glass tube, as well as the thickness and type of the phosphor used to coat the inner wall of the tube. CCFLs can also be formed into a wide range of shapes and sizes depending on the application.
Fluorescent lamps: Differences with hot cathode fluorescent lamps (HCFLs)
Fluorescent lamps and cold cathode fluorescent lamps have extremely similar constructions, but they use different types of electron discharge. Fluorescent lamps discharge electrons through a material called an emitter by heating electrodes, while CCFLs discharge electrons without heating, as described above. This is due to the construction of each lamp's electrode, and is the greatest difference between the two.
Main differences between cold and hot cathode fluorescent lamps
|
|
Cold cathode fluorescent lamps |
Hot cathode fluorescent lamps |
|---|---|---|
|
Lamp diameter |
1.8 to 5.0 mm |
15 to 32 mm |
|
Starting voltage |
High |
Low |
|
Tube current |
Low |
High |
|
Luminous flux |
Low |
High |
|
Luminous efficacy |
Low |
High |
|
Lifetime |
up to 60,000 hours |
3,000 to 15,000 hours |
|
Strong points |
Tube can be made thinner |
Highly efficient |
|
Longer lifetime |
Greater volume of light |
Features
- The ability to make a bright light source with a small diameter makes them suited as a light source for backlights. They hold up well to being turned on and off, and are earthquake resistant. The have low power consumption, which reduces increases in lamp temperature. They lave a long rated lifetime ? about 60,000 hours (depending on specifications).
Applications
Light sources for scanners and backlights for LCD televisions, LCD monitors, and the like, signs, lighting fixtures, etc.
