White Uniformity; Colour Purity; Luminance - Nokia 446PRO Service Manual

6.3. White Uniformity

Measurement conditions:
--- Full screen picture size, Brightness in middle 100 nit
--- Magnetic field
--- Warming up time 1 hour
Maximum variation between colour coordinates between any measurement points shall not vary
more than d(x),d(y) below.
Colour coordinates from corner to center:
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. 8.3

6.5. Luminance

--- Definition:
The following methodology and definition of luminance shall be applicable throughout
this specification.
Luminance shall be measured on 1280 x 1024 85 Hz pixel format at five areas, using two differ-
ent 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 +/ --- 20 nits (41 Ft ---L) 50*50 mm white field
L0 = 110 +/ --- 10 nits (32 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 =< 7 nits
The background shall be extinguished before brightness control reaches its end.
22
horizontal 0 Gauss
vertical 0.45 Gauss
L1
L0
L3
446F
L2
L4