White Uniformity; Contrast Ratio; White Color Adjustment - Philips 200BW8ES/00 Service Manual

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
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:
Product spec.
Production alignment spec.
Spec : =< 1.33 (In all ranges)
1000:1
9300K CIE coordinates
6500K/ sRGB CIE coordinates
sRGB CIE coordinates
50%
2
5
8
X = 0.283 ± 0.02
Y = 0.297 ± 0.02
X = 0.313 ± 0.02
Y = 0.329 ± 0.02
X = 0.313 ± 0.02
Y = 0.329 ± 0.02
200BW8 LCD
10%
10%
3
6 50%
9 90%
79