Philips 220EW8FS/00 Service Manual page 70

220EW8 LCD 70
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%
1
4
7
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
Min. value:
Typical value:
8.12 White color adjustment
There are three factory preset white color 9300K, 6500K, sRGB.
Apply full gray64 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:
8.13 Distance between TFT LCD monitor and CRT/TFT monitor
Conducted with different modes or frequencies. No interference in a distance down to 25 cm.
B_min
X 100%
B_max
50%
2
5
8
700:1(CPT)
1000:1(CPT)
10%
10%
3
6 50%
9 90%