<s>
On	O
2D	O
displays	O
,	O
such	O
as	O
computer	B-Device
monitors	I-Device
and	O
TVs	O
,	O
the	O
display	B-General_Concept
size	I-General_Concept
or	O
viewable	B-General_Concept
image	I-General_Concept
size	I-General_Concept
(	O
VIS	O
)	O
is	O
the	O
physical	O
size	O
of	O
the	O
area	O
where	O
pictures	O
and	O
videos	O
are	O
displayed	O
.	O
</s>
<s>
It	O
is	O
also	O
sometimes	O
called	O
the	O
physical	B-General_Concept
image	I-General_Concept
size	I-General_Concept
to	O
distinguish	O
it	O
from	O
the	O
"	O
logical	B-General_Concept
image	I-General_Concept
size	I-General_Concept
"	O
,	O
which	O
describes	O
a	O
screen	O
's	O
display	B-General_Concept
resolution	I-General_Concept
and	O
is	O
measured	O
in	O
pixels	O
.	O
</s>
<s>
It	O
is	O
also	O
sometimes	O
called	O
the	O
physical	B-General_Concept
image	I-General_Concept
size	I-General_Concept
to	O
distinguish	O
it	O
from	O
the	O
"	O
logical	B-General_Concept
image	I-General_Concept
size	I-General_Concept
,	O
"	O
which	O
describes	O
a	O
screen	O
's	O
display	B-General_Concept
resolution	I-General_Concept
and	O
is	O
measured	O
in	O
pixels	O
.	O
</s>
<s>
The	O
method	O
of	O
measuring	O
screen	B-General_Concept
size	I-General_Concept
by	O
its	O
diagonal	O
was	O
inherited	O
from	O
the	O
method	O
used	O
for	O
the	O
first	O
generation	O
of	O
CRT	O
television	O
,	O
when	O
picture	O
tubes	O
with	O
circular	O
faces	O
were	O
in	O
common	O
use	O
.	O
</s>
<s>
This	O
method	O
continued	O
even	O
when	O
cathode	O
ray	O
tubes	O
were	O
manufactured	O
as	O
rounded	O
rectangles	O
;	O
it	O
had	O
the	O
advantage	O
of	O
being	O
a	O
single	O
number	O
specifying	O
the	O
size	O
,	O
and	O
was	O
not	O
confusing	O
when	O
the	O
aspect	B-General_Concept
ratio	I-General_Concept
was	O
universally	O
4:3	O
.	O
</s>
<s>
In	O
the	O
US	O
,	O
when	O
virtually	O
all	O
TV	O
tubes	O
were	O
4:3	O
,	O
the	O
size	O
of	O
the	O
screen	O
was	O
given	O
as	O
the	O
true	O
screen	B-General_Concept
diagonal	I-General_Concept
with	O
a	O
V	O
following	O
it	O
(	O
this	O
was	O
a	O
requirement	O
in	O
the	O
US	O
market	O
but	O
not	O
elsewhere	O
)	O
.	O
</s>
<s>
This	O
was	O
not	O
misleading	O
for	O
the	O
consumer	O
as	O
the	O
seller	O
had	O
to	O
give	O
the	O
actual	O
screen	B-General_Concept
size	I-General_Concept
by	O
law	O
.	O
</s>
<s>
Flat	B-General_Concept
panel	I-General_Concept
displays	I-General_Concept
by	O
contrast	O
use	O
the	O
actual	O
diagonal	O
of	O
their	O
visible	O
display	B-General_Concept
size	I-General_Concept
,	O
thus	O
the	O
size	O
is	O
the	O
actual	O
size	O
presented	O
to	O
the	O
viewer	O
in	O
all	O
markets	O
.	O
</s>
<s>
This	O
means	O
that	O
a	O
similarly	O
specified	O
size	O
of	O
display	O
will	O
be	O
larger	O
as	O
a	O
flat	B-General_Concept
panel	I-General_Concept
display	I-General_Concept
compared	O
with	O
a	O
cathode	O
ray	O
tube	O
display	O
.	O
</s>
<s>
When	O
the	O
common	O
aspect	B-General_Concept
ratio	I-General_Concept
went	O
from	O
4:3	O
to	O
16:9	O
,	O
the	O
new	O
widescreens	O
were	O
labeled	O
with	O
a	O
W	O
in	O
the	O
US	O
.	O
</s>
<s>
Vizio	O
and	O
other	O
US	O
TV	O
manufacturers	O
have	O
introduced	O
even	O
wider	O
screens	O
with	O
a	O
21:9	O
aspect	B-General_Concept
ratio	I-General_Concept
in	O
order	O
to	O
match	O
aspect	O
ratios	O
used	O
in	O
cinemas	O
.	O
</s>
<s>
In	O
a	O
commercial	O
market	O
where	O
multiple	O
aspect	O
ratios	O
are	O
being	O
sold	O
,	O
it	O
will	O
always	O
take	O
two	O
numbers	O
to	O
describe	O
the	O
screen	B-General_Concept
size	I-General_Concept
,	O
some	O
combination	O
of	O
diagonal	O
,	O
aspect	B-General_Concept
ratio	I-General_Concept
,	O
height	O
or	O
width	O
.	O
</s>
<s>
As	O
an	O
example	O
,	O
in	O
some	O
cases	O
,	O
increasing	O
the	O
screen	B-General_Concept
size	I-General_Concept
by	O
even	O
0.1	O
"	O
can	O
cause	O
an	O
LCD	O
manufacturer	O
to	O
go	O
from	O
12	O
screens	O
fitting	O
on	O
their	O
glass	O
sheet	O
to	O
9	O
.	O
</s>
<s>
For	O
full	O
HDTV	B-Device
resolution	O
,	O
this	O
one	O
minute	O
of	O
arc	O
implies	O
that	O
the	O
TV	O
watcher	O
should	O
sit	O
4	O
times	O
the	O
height	O
of	O
the	O
screen	O
away	O
.	O
</s>
