Acer AL1913c, Service Manual

Page: 10 / 42

10
(1) Definition of Viewing Angle (
θ
x,
θ
y):
(2)
Definition of Contrast Ratio (CR):
The contrast ratio can be calculated by the following expression and figure
below.
Contrast Ratio (CR) = L255 / L0
L255: Luminance of gray level 255
L 0: Luminance of gray level 0
CR = CR (5)
CR (X) is corresponding to the Contrast Ratio of the point X at Figure in Note
(5).
Definition of luminance measured points and Brightness Uniformity:
12 o’clock direction
θ
y+
= 90º
6 o’clock
θ
y-
= 90º
θ
x-
θ
x
+
θ
y-
θ
y
+
x-
y+
y-
x+
Normal
θ
x =
θ
y = 0º
θ
X+
= 90º
θ
X-
= 90º
Active area
Vertical Line
N
umber
Horizontal Line Number
Horizontal Line Number [pixel]
: test point
X=1 to 5
5
1 2
3
0
320 640
960
1280
0
256
512
768
1024
X
4
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