15
13. Pixel defects on screens
5 Pixel
Rows
Sub-Pixel
Pixel
blue
green
red
5 P
ix
e
l
For active matrix TFTs with a resolution of 1920 x 1080 pixels, which are each
made up of three sub-pixels (red, green, blue), there are a total of approxi-
mately 6.2 million control transistors in use. Due to this very high number of
transistors and the associated extremely complex manufacturing process-
es used, occasionally one or more pixels can fail or become incorrectly con-
trolled.
The ISO standard ISO 9241-307 defines, amongst other things, the general-
ly applicable guidelines relating to pixel defects. Pixel defects are categorised
into four fault classes and three defect types. Every individual pixel consists of
three sub-pixels, each of which is assigned a basic colour (red, green, blue).
Pixel fault class
Defect type 1
Pixel constantly lit
Defect type 2
Pixel constantly black
Defect type 3
Defective sub-pixel
lit
black
0
0
0
0
0
I
1
1
2
1
0
1
3
5
II
2
2
5
5-n*
0
0
2xn*
10
III
5
15
50
50-n*
0
0
2xn*
100
IV
50
150
500
500-n*
0
0
2xn*
1000
n* = 1.5
The table describes the maximum number of pixel failures allowed on the screen, before a warranty claim arises. A war-
ranty claim may be applicable if the above number of defects in a category is exceeded.
