Philips 220CW8FB/00 Service Manual page 78

220CW8 LCD 78
Test resolution:
Test condition:
8.9.2 Brightness
To follow Panel specification. sRGB = 80 ± 10 nits.
8.9.3 Brightness uniformity
Set contrast at 100% and turn the brightness to get average above 300 nits at centre of the screen.
Apply the Fig 1, it should comply with the following formula:
Where B_max = Maximum brightness
B_min = Minimum brightness
8.10 White Uniformity
Definition of White Variation (δW):
Measure the luminance of gray level 255 at 9 points
δW = Maximum [L(1), L(2) ...... L(9)] / Minimum [L(1), L(2) ...... L(9)]
90%
8.11 Contrast ratio
The contrast ration can be calculated by following expression.
Contrast Ratio (CR) = L255 / L0
L255 : Luminance of gray level 255
L0 : Luminance of gray level 0
Typical value:
8.12 White color adjustment
There are three factory preset white color 9300K, 6500K, sRGB.
Apply full gray 64 pattern, with brightness in 100 % position and the contrast control at 50 % position.
The 1931 CIE Chromaticity (color triangle) diagram (x,y) coordinate for the screen center should be:
B_min
B_max
1
4
7
Spec : =< 1.33 (In all ranges)
1000:1
1680 x 1050 at 60 Hz
video input (RGB) = maximum white
X 100%>75%
50%
2
5
8
10%
10%
3
6 50%
9 90%