<s>
The	O
Retina	B-Operating_System
display	I-Operating_System
is	O
a	O
branded	O
series	O
of	O
IPS	B-Architecture
LCD	I-Architecture
and	O
OLED	B-Device
displays	I-Device
by	O
Apple	O
Inc	O
.	O
and	O
have	O
a	O
higher	O
pixel	B-Algorithm
density	I-Algorithm
than	O
their	O
traditional	O
displays	O
.	O
</s>
<s>
The	O
Retina	B-Operating_System
display	I-Operating_System
debuted	O
in	O
2010	O
with	O
the	O
iPhone	B-Operating_System
4	I-Operating_System
and	O
the	O
iPod	B-Operating_System
Touch	I-Operating_System
(	O
4th	O
Generation	O
)	O
,	O
and	O
later	O
the	O
iPad	B-Operating_System
(	O
3rd	O
generation	O
)	O
where	O
each	O
screen	O
pixel	O
of	O
the	O
iPhone	B-Operating_System
3GS	I-Operating_System
,	O
iPod	B-Operating_System
touch	I-Operating_System
(	O
3rd	O
generation	O
)	O
,	O
iPad	B-Operating_System
2	I-Operating_System
was	O
replaced	O
by	O
four	O
smaller	O
pixels	O
,	O
and	O
the	O
user	O
interface	O
scaled	B-Algorithm
up	I-Algorithm
to	O
fill	O
in	O
the	O
extra	O
pixels	O
.	O
</s>
<s>
Apple	O
calls	O
this	O
mode	O
HiDPI	B-Algorithm
mode	O
.	O
</s>
<s>
The	O
scale	O
factor	O
is	O
tripled	O
for	O
devices	O
with	O
even	O
higher	O
pixel	B-Algorithm
densities	I-Algorithm
,	O
such	O
as	O
the	O
iPhone	B-Operating_System
6	I-Operating_System
Plus	I-Operating_System
and	O
iPhone	B-Operating_System
X	I-Operating_System
.	O
</s>
<s>
The	O
advantage	O
of	O
this	O
equation	O
is	O
that	O
the	O
CPU	O
"	O
sees	O
"	O
a	O
small	O
portion	O
of	O
the	O
data	O
and	O
calculates	O
the	O
relative	O
positions	O
of	O
each	O
element	O
,	O
and	O
the	O
GPU	O
renders	O
these	O
elements	O
with	O
high	B-General_Concept
quality	I-General_Concept
assets	O
.	O
</s>
<s>
The	O
goal	O
of	O
Retina	B-Operating_System
displays	I-Operating_System
is	O
to	O
make	O
the	O
text	O
and	O
images	O
being	O
displayed	O
more	O
crisp	O
.	O
</s>
<s>
The	O
Retina	B-Operating_System
display	I-Operating_System
has	O
since	O
expanded	O
to	O
most	O
Apple	O
product	O
lines	O
,	O
such	O
as	O
Apple	B-Device
Watch	I-Device
,	O
iPhone	B-Operating_System
,	O
iPod	B-Operating_System
Touch	I-Operating_System
,	O
iPad	B-Operating_System
,	O
iPad	B-Device
Mini	I-Device
,	O
iPad	B-Device
Air	I-Device
,	O
iPad	B-Device
Pro	I-Device
,	O
MacBook	B-Device
,	O
MacBook	B-Device
Air	I-Device
,	O
MacBook	B-Device
Pro	I-Device
,	O
iMac	B-Device
,	O
and	O
Pro	B-Device
Display	I-Device
XDR	I-Device
,	O
some	O
of	O
which	O
have	O
never	O
had	O
a	O
comparable	O
non-Retina	O
display	O
.	O
</s>
<s>
Apple	O
uses	O
various	O
marketing	O
terms	O
to	O
differentiate	O
between	O
its	O
LCD	B-Device
and	O
OLED	B-Device
displays	I-Device
having	O
various	O
resolutions	B-General_Concept
,	O
contrast	O
levels	O
,	O
color	O
reproduction	O
,	O
or	O
refresh	O
rates	O
.	O
</s>
<s>
It	O
is	O
known	O
as	O
Liquid	B-Operating_System
Retina	I-Operating_System
display	O
for	O
the	O
iPhone	B-Operating_System
XR	I-Operating_System
,	O
iPad	B-Device
Air	I-Device
4th	I-Device
Generation	I-Device
,	O
iPad	B-Device
Mini	I-Device
6th	I-Device
Generation	I-Device
,	O
iPad	B-Device
Pro	I-Device
3rd	I-Device
Generation	I-Device
and	O
later	O
versions	O
,	O
and	O
Retina	O
4.5K	B-General_Concept
display	O
for	O
the	O
iMac	B-Device
.	O
</s>
<s>
Apple	O
's	O
Retina	B-Operating_System
displays	I-Operating_System
are	O
not	O
an	O
absolute	O
standard	O
for	O
display	O
sharpness	O
,	O
but	O
vary	O
depending	O
on	O
the	O
size	O
of	O
the	O
display	O
on	O
the	O
device	O
,	O
and	O
at	O
what	O
distance	O
the	O
user	O
would	O
typically	O
be	O
viewing	O
the	O
screen	O
.	O
</s>
<s>
Where	O
on	O
smaller	O
devices	O
with	O
smaller	O
displays	O
users	O
would	O
view	O
the	O
screen	O
at	O
a	O
closer	O
distance	O
to	O
their	O
eyes	O
,	O
the	O
displays	O
have	O
more	O
PPI	B-Algorithm
(	O
Pixels	B-Algorithm
Per	I-Algorithm
Inch	I-Algorithm
)	O
,	O
while	O
on	O
larger	O
devices	O
with	O
larger	O
displays	O
where	O
the	O
user	O
views	O
the	O
screen	O
further	O
away	O
,	O
the	O
screen	O
uses	O
a	O
lower	O
PPI	B-Algorithm
value	O
.	O
</s>
<s>
Later	O
device	O
versions	O
have	O
had	O
additional	O
improvements	O
,	O
whether	O
an	O
increase	O
in	O
the	O
screen	O
size	O
(	O
the	O
iPhone	B-Operating_System
12	I-Operating_System
Pro	I-Operating_System
Max	I-Operating_System
)	O
,	O
contrast	O
ratio	O
(	O
the	O
12.9	B-Device
”	I-Device
iPad	I-Device
Pro	I-Device
5th	I-Device
Generation	I-Device
,	O
and	O
iMac	B-Device
with	O
Retina	O
4.5K	B-General_Concept
display	O
)	O
,	O
and/or	O
,	O
more	O
recently	O
,	O
PPI	B-Algorithm
count	O
(	O
OLED	B-Device
iPhones	B-Operating_System
)	O
;	O
as	O
a	O
result	O
,	O
Apple	O
uses	O
the	O
names	O
“	O
Retina	B-Operating_System
HD	I-Operating_System
display	I-Operating_System
"	O
,	O
"	O
Retina	O
4K/5K	O
display	O
"	O
,	O
“	O
Retina	O
4.5K	B-General_Concept
display	O
"	O
,	O
"	O
Super	B-Operating_System
Retina	B-Operating_System
HD	I-Operating_System
display	I-Operating_System
"	O
,	O
“	O
Super	B-Operating_System
Retina	I-Operating_System
XDR	O
display	O
”	O
,	O
and	O
"	O
Liquid	B-Operating_System
Retina	I-Operating_System
display	O
"	O
for	O
each	O
successive	O
version	O
.	O
</s>
<s>
When	O
introducing	O
the	O
iPhone	B-Operating_System
4	I-Operating_System
,	O
Steve	O
Jobs	O
said	O
the	O
number	O
of	O
pixels	O
needed	O
for	O
a	O
Retina	B-Operating_System
display	I-Operating_System
is	O
about	O
300PPI	O
for	O
a	O
device	O
held	O
10	O
to	O
12	O
inches	O
from	O
the	O
eye	O
.	O
</s>
<s>
One	O
way	O
of	O
expressing	O
this	O
as	O
a	O
unit	O
is	O
pixels-per-degree	O
(	O
PPD	O
)	O
which	O
takes	O
into	O
account	O
both	O
the	O
screen	B-General_Concept
resolution	I-General_Concept
and	O
the	O
distance	O
from	O
which	O
the	O
device	O
is	O
viewed	O
.	O
</s>
<s>
Based	O
on	O
Jobs	O
 '	O
predicted	O
number	O
of	O
300	O
,	O
the	O
threshold	O
for	O
a	O
Retina	B-Operating_System
display	I-Operating_System
starts	O
at	O
the	O
PPD	O
value	O
of	O
57PPD	O
.	O
</s>
<s>
Note	O
that	O
the	O
PPD	O
parameter	O
is	O
not	O
an	O
intrinsic	O
parameter	O
of	O
the	O
display	O
itself	O
,	O
unlike	O
absolute	O
pixel	O
resolution	B-General_Concept
(	O
e.g.	O
</s>
<s>
1920×1080	O
pixels	O
)	O
or	O
relative	O
pixel	B-Algorithm
density	I-Algorithm
(	O
e.g.	O
</s>
<s>
where	O
is	O
the	O
distance	O
to	O
the	O
screen	O
and	O
is	O
the	O
resolution	B-General_Concept
of	O
the	O
screen	O
in	O
pixels	O
per	O
unit	O
length	O
.	O
</s>
<s>
In	O
practice	O
,	O
thus	O
far	O
Apple	O
has	O
converted	O
a	O
device	O
's	O
display	O
to	O
Retina	O
by	O
doubling	O
the	O
number	O
of	O
pixels	O
in	O
each	O
direction	O
,	O
quadrupling	O
the	O
total	O
resolution	B-General_Concept
.	O
</s>
<s>
The	O
sole	O
exception	O
to	O
this	O
has	O
been	O
the	O
iPhone	B-Operating_System
6	I-Operating_System
Plus	I-Operating_System
,	O
6S	B-Operating_System
Plus	I-Operating_System
,	O
7	B-Application
Plus	I-Application
,	O
and	O
8	B-Operating_System
Plus	I-Operating_System
,	O
which	O
renders	O
its	O
display	O
at	O
triple	O
the	O
number	O
of	O
pixels	O
in	O
each	O
direction	O
,	O
before	O
down-sampling	O
to	O
a	O
1080p	O
resolution	B-General_Concept
.	O
</s>
<s>
Currently	O
,	O
the	O
iPad	B-Operating_System
's	O
display	O
comes	O
from	O
Samsung	O
,	O
while	O
the	O
MacBook	B-Device
Pro	I-Device
and	O
iPod	B-Operating_System
Touch	I-Operating_System
displays	O
are	O
made	O
by	O
LG	O
Display	O
and	O
Japan	O
Display	O
Inc	O
.	O
</s>
<s>
There	O
was	O
a	O
shift	O
of	O
display	O
technology	O
from	O
twisted	O
nematic	O
(	O
TN	O
)	O
liquid-crystal	B-Device
displays	I-Device
(	O
LCDs	B-Device
)	O
to	O
in-plane	B-Architecture
switching	I-Architecture
(	O
IPS	B-Architecture
)	O
LCDs	B-Device
starting	O
with	O
the	O
iPhone	B-Operating_System
4	I-Operating_System
models	O
in	O
June	O
2010	O
.	O
</s>
<s>
Apple	O
markets	O
the	O
following	O
devices	O
as	O
having	O
a	O
Retina	B-Operating_System
display	I-Operating_System
,	O
Retina	B-Operating_System
HD	I-Operating_System
display	I-Operating_System
,	O
Liquid	B-Operating_System
Retina	B-Operating_System
display	I-Operating_System
,	O
Liquid	B-Operating_System
Retina	I-Operating_System
XDR	O
display	O
,	O
Super	B-Operating_System
Retina	B-Operating_System
HD	I-Operating_System
display	I-Operating_System
,	O
Super	B-Operating_System
Retina	I-Operating_System
XDR	O
display	O
or	O
Retina	O
4K/5K/6K	O
display	O
:	O
</s>
<s>
Model	O
Marketing	O
name	O
Screen	O
size	O
Resolution	B-General_Concept
AspectRatio	O
Pixel	B-Algorithm
density	I-Algorithm
Pixel	O
size	O
( µm	O
)	O
Angular	O
pixel	O
density( 	O
px/	O
°	O
;	O
at	O
distance	O
)	O
typ	O
.	O
</s>
<s>
viewing	O
distance	O
Total	O
pixels	O
ppi	B-Algorithm
px/cm	O
Apple	B-Device
Watch	I-Device
38mm	O
Retina	B-Operating_System
display	I-Operating_System
272×340	O
4:5	O
326	O
128	O
77.9	O
56.9	O
92,480	O
Apple	B-Device
Watch	I-Device
42mm	O
312×390	O
121,680	O
Apple	B-Device
Watch	I-Device
40mm	O
324×394	O
127,656	O
Apple	B-Device
Watch	I-Device
44mm	O
368×448	O
164,864	O
Apple	B-Device
Watch	I-Device
41mm	O
352×430	O
151,360	O
Apple	B-Device
Watch	I-Device
45mm	O
396×484	O
191,664	O
Apple	B-Device
Watch	I-Device
49mm	O
410×502	O
338	O
133	O
75.2	O
59.0	O
205,820	O
iPhone	B-Operating_System
4	I-Operating_System
,	O
4S	B-Operating_System
and	O
iPod	B-Operating_System
Touch	I-Operating_System
4	I-Operating_System
960×640	O
2:3	O
326	O
128	O
77.9	O
56.9	O
614,400	O
iPhone	B-Operating_System
5	I-Operating_System
,	O
5C	B-Operating_System
,	O
5S	B-Operating_System
and	O
SE	B-Operating_System
1	I-Operating_System
,	O
iPod	B-Operating_System
Touch	I-Operating_System
5	I-Operating_System
,	O
6	B-Device
and	O
7	B-Application
1136×	O
6409:16	O
727,040	O
iPhone	B-Operating_System
6	I-Operating_System
,	O
6S	B-Operating_System
,	O
7	B-Application
,	O
8	B-Device
,	O
SE	B-Operating_System
2	I-Operating_System
and	O
SE	O
3Retina	O
HD	O
display	O
1334×750	O
1,000,500	O
iPhone	B-Operating_System
6	I-Operating_System
Plus	I-Operating_System
,	O
6S	B-Operating_System
Plus	I-Operating_System
,	O
7	B-Application
Plus	I-Application
and	O
8	B-Operating_System
Plus	I-Operating_System
1920×1080	O
401	O
158	O
63.3	O
70.0	O
2,073,600	O
iPhone	B-Operating_System
XR	I-Operating_System
and	O
11	B-Operating_System
Liquid	B-Operating_System
Retina	B-Operating_System
display	I-Operating_System
1792×	O
8286:13	O
(	O
9:19.5	O
)	O
326	O
128	O
77.9	O
56.9	O
1,483,776	O
iPhone	B-Operating_System
12	I-Operating_System
Mini	I-Operating_System
and	O
13	B-Operating_System
MiniSuper	O
Retina	O
HD/XDR	O
display	O
2340×1080	O
476/337	O
187/133	O
53.4	O
83.1	O
2,527,200	O
iPhone	B-Operating_System
X	I-Operating_System
,	O
XS	B-Operating_System
,	O
and	O
11	B-Operating_System
Pro	I-Operating_System
2436×1125	O
458/324Due	O
to	O
the	O
peculiar	O
diamond	O
Sub-Pixels	O
layout	O
found	O
in	O
the	O
iPhone	B-Operating_System
X	I-Operating_System
,	O
iPhone	B-Operating_System
XS	I-Operating_System
and	O
iPhone	B-Operating_System
XS	I-Operating_System
Max	I-Operating_System
,	O
the	O
actual	O
density	O
of	O
the	O
Red	O
and	O
Blue	O
Sub-Pixels	O
is	O
lower	O
than	O
that	O
of	O
the	O
Green	O
Sub-Pixels	O
,	O
being	O
reportedly	O
324	O
Sub-Pixels	O
per	O
inch	O
.	O
</s>
<s>
Reviews	O
of	O
Apple	O
devices	O
with	O
Retina	B-Operating_System
displays	I-Operating_System
have	O
generally	O
been	O
positive	O
on	O
technical	O
grounds	O
,	O
with	O
comments	O
describing	O
it	O
as	O
a	O
considerable	O
improvement	O
on	O
earlier	O
screens	O
and	O
praising	O
Apple	O
for	O
driving	O
third-party	O
application	O
support	O
for	O
high-resolution	O
displays	O
more	O
effectively	O
than	O
on	O
Windows	B-Application
.	O
</s>
<s>
Reviewing	O
the	O
iPhone	B-Operating_System
4	I-Operating_System
in	O
2010	O
,	O
Joshua	O
Topolsky	O
commented	O
:	O
</s>
<s>
Not	O
only	O
are	O
the	O
colors	O
and	O
blacks	O
deep	O
and	O
rich	O
,	O
but	O
you	O
simply	O
cannot	O
see	O
pixels	O
on	O
the	O
screen	O
…	O
webpages	O
that	O
would	O
be	O
line	O
after	O
line	O
of	O
pixelated	O
content	O
when	O
zoomed	O
out	O
on	O
a	O
3GS	O
are	O
completely	O
readable	O
on	O
the	O
iPhone	B-Operating_System
4	I-Operating_System
,	O
though	O
the	O
text	O
is	O
beyond	O
microscopic.	O
"	O
</s>
<s>
That	O
much	O
resolution	B-General_Concept
is	O
stunning	O
.	O
</s>
<s>
To	O
see	O
it	O
on	O
a	O
mainstream	O
device	O
like	O
the	O
iPad	B-Operating_System
—	O
rather	O
than	O
a	O
$	O
13,000	O
exotic	O
monitor	O
—	O
is	O
truly	O
amazing	O
,	O
and	O
something	O
I	O
've	O
been	O
waiting	O
more	O
than	O
a	O
decade	O
to	O
see	O
.	O
</s>
<s>
It	O
will	O
set	O
a	O
bar	O
for	O
future	O
resolution	B-General_Concept
that	O
every	O
other	O
manufacturer	O
of	O
devices	O
and	O
PCs	O
will	O
have	O
to	O
jump	O
.	O
</s>
<s>
Writer	O
John	O
Gruber	O
suggested	O
that	O
the	O
arrival	O
of	O
Retina	B-Operating_System
displays	I-Operating_System
on	O
computers	O
would	O
trigger	O
a	O
need	O
to	O
redesign	O
interfaces	O
and	O
designs	O
for	O
the	O
new	O
displays	O
:	O
</s>
<s>
Fonts	O
optimized	O
for	O
screen	O
rendering	O
look	O
cheap	O
on	O
the	O
retina	O
MacBook	B-Device
Pro	I-Device
—	O
sometimes	O
downright	O
cheesy	O
—	O
in	O
the	O
same	O
way	O
they	O
do	O
when	O
printed	O
in	O
a	O
glossy	O
magazine	O
.	O
</s>
<s>
He	O
says	O
that	O
the	O
physiology	O
of	O
the	O
human	O
retina	O
is	O
such	O
that	O
there	O
must	O
be	O
at	O
least	O
477	O
pixels	B-Algorithm
per	I-Algorithm
inch	I-Algorithm
in	O
a	O
pixelated	O
display	O
for	O
the	O
pixels	O
to	O
become	O
imperceptible	O
to	O
the	O
human	O
eye	O
at	O
a	O
distance	O
of	O
.	O
</s>
<s>
Astronomer	O
and	O
science	O
blogger	O
Phil	O
Plait	O
notes	O
,	O
however	O
,	O
that	O
,	O
"	O
if	O
you	O
have	O
[	O
better	O
than	O
20/20	O
]	O
eyesight	O
,	O
then	O
at	O
one	O
foot	O
away	O
the	O
iPhone	B-Operating_System
4S	I-Operating_System
's	O
pixels	O
are	O
resolved	O
.	O
</s>
<s>
Apple	O
fan	O
website	O
CultOfMac	O
hosts	O
an	O
article	O
by	O
John	O
Brownlee	O
who	O
incorrectly	O
stated	O
that	O
the	O
resolution	B-General_Concept
the	O
human	O
eye	O
can	O
discern	O
at	O
12inches	O
is	O
900PPI	O
,	O
concluding	O
"	O
Apple	O
's	O
Retina	B-Operating_System
Displays	I-Operating_System
are	O
only	O
about	O
33%	O
of	O
the	O
way	O
there.	O
"	O
</s>
<s>
However	O
,	O
near	O
visual	O
acuity	O
is	O
usually	O
poor	O
due	O
to	O
presbyopia	O
in	O
nearly	O
everyone	O
over	O
40	O
,	O
such	O
that	O
decreasing	O
reading	O
distance	O
can	O
actually	O
reduce	O
perceivable	O
resolution	B-General_Concept
.	O
</s>
<s>
The	O
first	O
smartphone	O
following	O
the	O
iPhone	B-Operating_System
4	I-Operating_System
to	O
ship	O
with	O
a	O
display	O
of	O
a	O
comparable	O
pixel	B-Algorithm
density	I-Algorithm
was	O
the	O
Nokia	O
E6	O
,	O
running	O
Symbian	B-Operating_System
Anna	I-Operating_System
,	O
with	O
a	O
resolution	B-General_Concept
of	O
640	O
×	O
480	O
at	O
a	O
screen	O
size	O
of	O
62.5mm	O
.	O
</s>
<s>
This	O
was	O
an	O
isolated	O
case	O
for	O
the	O
platform	O
however	O
,	O
as	O
all	O
other	O
Symbian-based	O
devices	O
had	O
larger	O
displays	O
with	O
lower	O
resolutions	B-General_Concept
.	O
</s>
<s>
Some	O
older	O
Symbian	B-Operating_System
smartphones	O
,	O
including	O
the	O
Nokia	O
N80	O
and	O
N90	B-Language
,	O
featured	O
a	O
2.1	O
inch	O
display	O
at	O
259	O
ppi	B-Algorithm
,	O
which	O
was	O
one	O
of	O
the	O
sharpest	O
at	O
the	O
time	O
.	O
</s>
<s>
The	O
first	O
Android	O
smartphones	O
with	O
the	O
same	O
display	O
-	O
Meizu	B-Application
M9	I-Application
was	O
launched	O
a	O
few	O
months	O
later	O
in	O
beginning	O
of	O
2011	O
.	O
</s>
<s>
In	O
October	O
of	O
the	O
same	O
year	O
Galaxy	B-Application
Nexus	I-Application
was	O
announced	O
,	O
which	O
had	O
a	O
display	O
with	O
a	O
better	O
resolution	B-General_Concept
.	O
</s>
<s>
By	O
2013	O
the	O
300+ppimark	O
was	O
found	O
on	O
midrange	O
phones	O
such	O
as	O
the	O
Moto	B-Device
G	I-Device
.	O
From	O
2013	O
to	O
2014	O
,	O
many	O
flagship	O
devices	O
such	O
as	O
the	O
Samsung	B-Application
Galaxy	I-Application
S4	I-Application
and	O
HTC	B-Application
One	I-Application
(	O
M8	O
)	O
had	O
1080p	O
(	O
FHD	O
)	O
screens	O
around	O
5-inches	O
for	O
a	O
400+	O
PPI	B-Algorithm
which	O
surpassed	O
the	O
Retina	O
density	O
on	O
the	O
iPhone	B-Operating_System
5	I-Operating_System
.	O
</s>
<s>
The	O
second	O
major	O
redesign	O
of	O
the	O
iPhone	B-Operating_System
,	O
the	O
iPhone	B-Operating_System
6	I-Operating_System
,	O
has	O
a	O
1334	O
×	O
750	O
resolution	B-General_Concept
on	O
a	O
4.7-inch	O
screen	O
,	O
while	O
rivals	O
such	O
as	O
the	O
Samsung	B-Application
Galaxy	I-Application
S6	I-Application
have	O
a	O
QHD	O
display	O
of	O
2560	O
×	O
1440	O
resolution	B-General_Concept
,	O
close	O
to	O
four	O
times	O
the	O
number	O
of	O
pixels	O
found	O
in	O
the	O
iPhone	B-Operating_System
6	I-Operating_System
,	O
giving	O
the	O
S6	O
a	O
577	O
PPI	B-Algorithm
that	O
is	O
almost	O
twice	O
that	O
of	O
the	O
iPhone	B-Operating_System
6	I-Operating_System
's	O
326	O
PPI	B-Algorithm
.	O
</s>
<s>
The	O
Sony	O
Xperia	O
Z5	O
Premium	O
launched	O
in	O
late	O
2015	O
had	O
806	O
PPI	B-Algorithm
.	O
</s>
<s>
The	O
larger	O
iPhone	B-Operating_System
6	I-Operating_System
Plus	I-Operating_System
features	O
a	O
"	O
Retina	B-Operating_System
HD	I-Operating_System
display	I-Operating_System
"	O
,	O
which	O
is	O
a	O
5.5-inch	O
1080p	O
screen	O
with	O
401	O
PPI	B-Algorithm
.	O
</s>
<s>
Aside	O
from	O
resolution	B-General_Concept
,	O
all	O
generations	O
of	O
iPhone	B-Operating_System
Retina	B-Operating_System
displays	I-Operating_System
receive	O
high	O
ratings	O
for	O
other	O
aspects	O
such	O
as	O
brightness	O
and	O
color	O
accuracy	O
,	O
compared	O
to	O
those	O
of	O
contemporary	O
smartphones	O
,	O
while	O
some	O
Android	O
devices	O
such	O
as	O
the	O
LG	B-Application
G3	I-Application
have	O
sacrificed	O
screen	O
quality	O
and	O
battery	O
life	O
for	O
high	O
resolution	B-General_Concept
.	O
</s>
<s>
Many	O
Windows-based	O
Ultrabook	B-Device
models	O
have	O
offered	O
1080p	O
(	O
FHD	O
)	O
screens	O
standard	O
since	O
2012	O
and	O
often	O
QHD	O
or	O
QHD+	O
as	O
optional	O
upgrade	O
displays	O
.	O
</s>
