<s>
A	O
defective	B-General_Concept
pixel	I-General_Concept
is	O
a	O
pixel	B-Algorithm
on	O
a	O
liquid	B-Device
crystal	I-Device
display	I-Device
(	O
LCD	B-Device
)	O
that	O
is	O
not	O
functioning	O
properly	O
.	O
</s>
<s>
The	O
ISO	O
standard	O
ISO	B-General_Concept
13406-2	I-General_Concept
distinguishes	O
between	O
three	O
different	O
types	O
of	O
defective	B-General_Concept
pixels	I-General_Concept
,	O
while	O
hardware	O
companies	O
tend	O
to	O
have	O
further	O
distinguishing	O
types	O
.	O
</s>
<s>
Similar	O
defects	O
can	O
also	O
occur	O
in	O
charge-coupled	B-Algorithm
device	I-Algorithm
(	O
CCD	O
)	O
and	O
CMOS	B-Device
image	B-Algorithm
sensors	I-Algorithm
in	O
digital	O
cameras	O
.	O
</s>
<s>
In	O
these	O
devices	O
,	O
defective	B-General_Concept
pixels	I-General_Concept
fail	O
to	O
sense	O
light	O
levels	O
correctly	O
,	O
whereas	O
defective	B-General_Concept
pixels	I-General_Concept
in	O
LCDs	B-Device
fail	O
to	O
reproduce	O
light	O
levels	O
correctly	O
.	O
</s>
<s>
A	O
dark	O
dot	O
defect	O
is	O
usually	O
caused	O
by	O
a	O
transistor	B-Application
in	O
the	O
transparent	O
electrode	O
layer	O
that	O
is	O
stuck	O
"	O
on	O
"	O
for	O
TN	O
panels	O
or	O
"	O
off	O
"	O
for	O
MVA	O
,	O
PVA	O
,	O
and	O
IPS	O
panels	O
.	O
</s>
<s>
In	O
that	O
state	O
,	O
the	O
transistor	B-Application
places	O
the	O
liquid	B-Device
crystal	I-Device
material	O
so	O
that	O
no	O
light	O
ever	O
passes	O
through	O
to	O
the	O
RGB	O
layer	O
of	O
the	O
display	O
.	O
</s>
<s>
A	O
bright	O
dot	O
defect	O
or	O
hot	B-Device
pixel	I-Device
is	O
a	O
group	O
of	O
three	O
sub-pixels	O
(	O
one	O
pixel	B-Algorithm
)	O
all	O
of	O
whose	O
transistors	B-Application
are	O
"	O
off	O
"	O
for	O
TN	O
panels	O
or	O
stuck	O
"	O
on	O
"	O
for	O
MVA	O
and	O
PVA	O
panels	O
.	O
</s>
<s>
This	O
allows	O
all	O
light	O
to	O
pass	O
through	O
to	O
the	O
RGB	O
layer	O
,	O
creating	O
a	O
bright	O
white	O
pixel	B-Algorithm
that	O
is	O
always	O
on	O
.	O
</s>
<s>
A	O
partial	O
sub-pixel	O
defect	O
is	O
a	O
manufacturing	O
defect	O
in	O
which	O
the	O
RGB	O
film	O
layer	O
was	O
not	O
cut	O
properly	O
.	O
</s>
<s>
A	O
tape	O
automated	O
bonding	O
fault	O
(	O
TAB	O
fault	O
)	O
is	O
caused	O
by	O
a	O
connection	O
failure	O
from	O
the	O
TAB	O
that	O
connects	O
the	O
transparent	O
electrode	O
layers	O
to	O
the	O
video	O
driver	O
board	O
of	O
an	O
LCD	B-Device
.	O
</s>
<s>
TAB	O
is	O
one	O
of	O
several	O
methods	O
employed	O
in	O
the	O
LCD-manufacturing	O
process	O
to	O
electrically	O
connect	O
hundreds	O
of	O
signal	O
paths	O
going	O
to	O
the	O
rows	O
and	O
columns	O
of	O
electrodes	O
in	O
layer	O
6	O
(	O
the	O
transparent	O
electrode	O
layer	O
)	O
in	O
the	O
LCD	B-Device
to	O
the	O
video	O
integrated	O
circuits	O
(	O
ICs	O
)	O
on	O
the	O
driver	O
board	O
that	O
drives	O
these	O
electrodes	O
.	O
</s>
<s>
If	O
an	O
LCD	B-Device
is	O
subjected	O
to	O
physical	O
shock	O
,	O
this	O
could	O
cause	O
one	O
or	O
more	O
TAB	O
connections	O
to	O
fail	O
inside	O
the	O
display	O
.	O
</s>
<s>
TAB	O
faults	O
require	O
the	O
replacement	O
of	O
the	O
LCD	B-Device
module	I-Device
itself	O
.	O
</s>
<s>
If	O
these	O
connections	O
were	O
to	O
fail	O
,	O
the	O
effect	O
would	O
be	O
that	O
an	O
entire	O
row	O
or	O
column	O
of	O
pixels	B-Algorithm
would	O
fail	O
to	O
activate	O
.	O
</s>
<s>
Hardware	O
manufacturers	O
and	O
distributors	O
claim	O
that	O
TAB	O
faults	O
,	O
as	O
opposed	O
to	O
other	O
physical	O
defects	O
found	O
in	O
an	O
LCD	B-Device
,	O
do	O
not	O
allow	O
for	O
repair	O
.	O
</s>
<s>
A	O
stuck	O
sub-pixel	O
is	O
a	O
pixel	B-Algorithm
that	O
is	O
always	O
"	O
on	O
"	O
.	O
</s>
<s>
This	O
is	O
usually	O
caused	O
by	O
a	O
transistor	B-Application
that	O
is	O
getting	O
power	O
all	O
the	O
time	O
(	O
VA/IPS	O
)	O
or	O
not	O
getting	O
any	O
power	O
(	O
TN	O
)	O
and	O
is	O
therefore	O
continuously	O
allowing	O
light	O
at	O
that	O
point	O
to	O
pass	O
through	O
to	O
the	O
RGB	O
layer	O
.	O
</s>
<s>
Any	O
given	O
pixel	B-Algorithm
will	O
stay	O
red	O
,	O
blue	O
,	O
or	O
green	O
and	O
will	O
not	O
change	O
when	O
attempting	O
to	O
display	O
an	O
image	O
.	O
</s>
<s>
These	O
pixels	B-Algorithm
may	O
only	O
show	O
up	O
using	O
certain	O
applications	O
,	O
or	O
they	O
may	O
be	O
on	O
all	O
the	O
time	O
.	O
</s>
<s>
In	O
LCD	B-Device
manufacture	O
,	O
it	O
is	O
common	O
for	O
a	O
display	O
to	O
be	O
manufactured	O
with	O
several	O
sub-pixel	O
defects	O
(	O
each	O
pixel	B-Algorithm
is	O
composed	O
of	O
three	O
primary-colored	O
sub-pixels	O
)	O
.	O
</s>
<s>
The	O
number	O
of	O
faulty	O
pixels	B-Algorithm
tolerated	O
before	O
a	O
screen	O
is	O
rejected	O
,	O
is	O
dependent	O
on	O
the	O
class	O
that	O
the	O
manufacturer	O
has	O
given	O
the	O
display	O
(	O
although	O
officially	O
described	O
by	O
the	O
ISO	B-General_Concept
13406-2	I-General_Concept
standard	O
,	O
not	O
all	O
manufacturers	O
interpret	O
this	O
standard	O
the	O
same	O
way	O
,	O
or	O
follow	O
it	O
at	O
all	O
)	O
.	O
</s>
<s>
Some	O
manufacturers	O
have	O
a	O
zero-tolerance	O
policy	O
with	O
regard	O
to	O
LCD	B-Device
screens	I-Device
,	O
rejecting	O
all	O
units	O
found	O
to	O
have	O
any	O
number	O
of	O
(	O
sub	O
-	O
)	O
pixel	B-Algorithm
defects	O
.	O
</s>
<s>
Other	O
manufacturers	O
reject	O
displays	O
according	O
to	O
the	O
number	O
of	O
total	O
defects	O
,	O
the	O
number	O
of	O
defects	O
in	O
a	O
given	O
group	O
(	O
e.g.	O
,	O
one	O
dead	B-General_Concept
pixel	I-General_Concept
or	O
three	O
stuck	O
sub-pixels	O
in	O
a	O
five-by-five	O
pixel	B-Algorithm
area	O
)	O
,	O
or	O
other	O
criteria	O
.	O
</s>
<s>
In	O
some	O
cases	O
,	O
a	O
manufacturer	O
sends	O
all	O
screens	O
to	O
sale	O
then	O
replaces	O
the	O
screen	O
if	O
the	O
customer	O
reports	O
the	O
unit	O
as	O
faulty	O
and	O
the	O
defective	B-General_Concept
pixels	I-General_Concept
meet	O
their	O
minimum	O
requirements	O
for	O
return	O
.	O
</s>
<s>
Some	O
screens	O
come	O
with	O
a	O
leaflet	O
stating	O
how	O
many	O
dead	B-General_Concept
pixels	I-General_Concept
they	O
are	O
allowed	O
to	O
have	O
before	O
the	O
owner	O
can	O
send	O
them	O
back	O
to	O
the	O
manufacturer	O
.	O
</s>
<s>
Dead	B-General_Concept
pixels	I-General_Concept
may	O
tend	O
to	O
occur	O
in	O
clusters	O
;	O
in	O
most	O
cases	O
,	O
displays	O
with	O
such	O
a	O
cluster	O
problem	O
can	O
be	O
sent	O
back	O
to	O
the	O
manufacturer	O
.	O
</s>
