FEASA LED ANALYSER
ICT VERSION
Setting Tolerance Limits for Colour and Intensity
The test procedure requires the user to set the Pass/Fail limits for Colour and Intensity for each
LED which then become the standard against which LEDs to be tested are compared.
The Pass/Fail limits for Colour are chosen, in conjunction with manufacturer’s specifications,
from measurements taken from a sample number of typical LEDs.
Because Hue is expressed as a single number it is more convenient to set the limits for the
colour in terms of their Hue value.
Sample Hue Pass/Fail Limits
LED Minimum Maximum
Red 0 2
Green 110 130
Blue 220 250
Amber 2 10
Yellow 80 110
Orange 10 20
The Saturation value must be taken into account when testing White LED's. The Saturation is
a value between 0% and 100%. A pure white will have a value close to 0% while a pure
colour will have a value close to 100%.
The Pass/Fail limits for intensity are chosen from the average intensity values from a number
of sample LEDs.
Sample Intensity Pass/Fail Limits in Auto Mode
Intensity
Value
Upper
Limit
Lower
Limit
Comments
125 150 100 Very Dim LED, Recommend using Maunal
Capture Range C3
20000 25000 16000 Average LED, Recommend using Manual
Capture Range, C2 or C3
60000 65000 56000 Bright LED, Auto capture use is OK
Note:- the Intensity Value will depend on the Range selected
Note:- Feasa recommends setting the Capture Range to give Intensity Values of 55K to 85K.
Figure 5.
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