White Uniformity; Luminance - Nokia 445PRO Service Manual

6.3 White Uniformity

Measurement conditions:
--- Full screen picture size, Brightness in middle 100 nit
--- Magnetic field horizontal
vertical
--- Warming up time 1 hour
Maximum variation between colour coordinates between any measurement points shall not vary
more than d(x),d(y) below.
d(x) = ± 0.015
d(y) = ± 0.015
6.4 Colour Purity
There should not be visual discoloration with each of the red, green and blue beams after the tube is
moved to any directions.
Measurement conditions: same as spec. 6.3

6.5 Luminance

Definition:
The following methodology and definition of luminance shall be applicable throughout this specifica-
tion
Luminance shall be measured on 1600 x 1280@85 Hz pixel format at five areas, using two different
pictures:
--- 1. In the center of the screen white field 50*50 mm
--- 2. Full white field.
The five areas are defined as:
L0 Center of the screen
L1 Upper left of the screen
L2 Upper right of the screen
L3 Lower left of the screen
L4 Lower right of the screen
Requirements:
Maximum contrast luminance:
With the brightness control set so that background brightness is 1 nit and the contrast control set to
maximum.
L0 = 140 30 nits (40.9Ft ---L) 50*50 mm white field
L0 = 110 10 nits (29.4 Ft ---L) Full white field
Minimum luminance:
Using full white picture, with the brightness and contrast controls in minimum, the foreground full
white field (L0) < 5 nits.
Background luminance:
The luminance of the background, measured at center of the screen without active video and in the
absence of significant ambient illumination, brightness at maximum must be:
1 nit.± L0 ± 10 nits
The background shall be extinguished before brightness control reaches its end.
Luminance uniformity:
With the brightness control set so that the background raster is just extinguished the contrast con-
trol set for L0 = 100 nits, ( 29.2 Ft ---L), luminance on areas L1, L2, L3 and L4 shall be greater than
(80 %) of L0.(80 nits, 23 Ft ---L)
0 Gauss
0.45 Gauss
L1 L2
L0
L3 L4
445N
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