FEASA LED ANALYSER
ICT VERSION
White LED's
White LED's must be treated differently to Coloured LED's when being tested. White is not a
Colour – it is a mix of all other Colours. The three Primary Colours Red, Green and Blue will
be mixed in approximately equal proportions to display a White Colour. The Saturation values
must be used when testing White LED's. The Saturation is a value between 0% and 100%. A
value of 0% indicates a pure white and a value of 100% indicates a pure Colour.
In reality, the Saturation value of white LED's vary significantly with values of 30% being
typical. Remember, the Saturation value is an indication of how white is the LED being tested.
The correct values must be determined experimentally with the particular LED's to be tested.
Most LED manufacturers will specify their white LED's using Chromaticity co-ordinates xy. This
is a two-dimensional Chart with x on the horizontal axis and x on the vertical axis. The range
of x and x lies between 0 and 1.
y
x
Figure 4. CIE 1931 Chromaticity Co-Ordinates
White LED's will have approximate co-ordinates of 0.33, 0.33. This may vary depending on
the manufacturer of the LED where some LED's will have a Blue tint (Cool White) and other
LED's will have a Red tint (Warm White).
Back to Index
12
To Next Page
Loading...
Need help?
General
