<s>
microLED	B-General_Concept
,	O
also	O
known	O
as	O
micro-LED	B-General_Concept
,	O
mLED	B-General_Concept
or	O
µLED	O
is	O
an	O
emerging	O
flat-panel	B-General_Concept
display	I-General_Concept
technology	O
consisting	O
of	O
arrays	O
of	O
microscopic	O
LEDs	O
forming	O
the	O
individual	O
pixel	B-Algorithm
elements	O
.	O
</s>
<s>
The	O
first	O
high-resolution	O
and	O
video-capable	O
InGaN	O
microLED	B-General_Concept
microdisplay	O
in	O
VGA	O
format	O
was	O
realized	O
in	O
2009	O
by	O
Hongxing	O
Jiang	O
and	O
Jingyu	O
Lin	O
and	O
their	O
colleagues	O
at	O
Texas	O
Tech	O
University	O
and	O
III-N	O
Technology	O
,	O
Inc	O
.	O
via	O
active	O
driving	O
of	O
microLED	B-General_Concept
array	O
by	O
a	O
complementary	O
metal-oxide	O
semiconductor	O
(	O
CMOS	O
)	O
IC	O
.	O
</s>
<s>
Compared	O
to	O
widespread	O
LCD	B-Device
technology	O
,	O
microLED	B-General_Concept
displays	O
offer	O
better	O
contrast	O
,	O
response	O
times	O
,	O
and	O
energy	O
efficiency	O
.	O
</s>
<s>
MicroLED	B-General_Concept
offers	O
greatly	O
reduced	O
energy	O
requirements	O
when	O
compared	O
to	O
conventional	O
LCD	B-Device
displays	I-Device
while	O
also	O
offering	O
pixel-level	O
light	O
control	O
and	O
a	O
high	O
contrast	O
ratio	O
.	O
</s>
<s>
The	O
inorganic	O
nature	O
of	O
microLEDs	B-General_Concept
gives	O
them	O
a	O
longer	O
lifetime	O
advantage	O
over	O
OLEDs	B-Device
and	O
allows	O
them	O
to	O
display	O
brighter	O
images	O
with	O
minimal	O
risk	O
of	O
screen	B-General_Concept
burn-in	I-General_Concept
.	O
</s>
<s>
The	O
sub-nanosecond	O
response	O
time	O
of	O
µLED	O
has	O
a	O
huge	O
advantage	O
over	O
other	O
display	O
technologies	O
for	O
3D/AR/VR	O
displays	O
since	O
these	O
devices	O
need	O
more	O
images	O
,	O
more	O
pixels	B-Algorithm
per	O
image	O
,	O
more	O
frames	O
per	O
second	O
and	O
fast	O
response	O
.	O
</s>
<s>
,	O
microLED	B-General_Concept
displays	O
have	O
not	O
been	O
mass-produced	O
,	O
although	O
Sony	O
,	O
Samsung	B-Application
,	O
and	O
Konka	O
sell	O
microLED	B-General_Concept
video	B-Device
walls	I-Device
.	O
</s>
<s>
Sony	O
already	O
sells	O
microLED	B-General_Concept
displays	O
as	O
a	O
replacement	O
for	O
conventional	O
cinema	O
screens	O
.	O
</s>
<s>
BOE	O
,	O
Epistar	O
,	O
and	O
Leyard	O
have	O
plans	O
for	O
microLED	B-General_Concept
mass	O
production	O
.	O
</s>
<s>
MicroLED	B-General_Concept
can	O
be	O
made	O
flexible	B-Application
and	O
transparent	B-Device
,	O
just	O
like	O
OLEDs	B-Device
.	O
</s>
<s>
Inorganic	O
semiconductor	O
microLED	B-General_Concept
( µLED	O
)	O
technology	O
was	O
first	O
invented	O
in	O
2000	O
by	O
the	O
research	O
group	O
of	O
Hongxing	O
Jiang	O
and	O
Jingyu	O
Lin	O
of	O
Texas	O
Tech	O
University	O
while	O
they	O
were	O
at	O
Kansas	O
State	O
University	O
.	O
</s>
<s>
Following	O
their	O
first	O
report	O
of	O
electrical	O
injection	O
microLEDs	B-General_Concept
based	O
on	O
indium	O
gallium	O
nitride	O
(	O
InGaN	O
)	O
semiconductors	O
,	O
several	O
groups	O
have	O
quickly	O
engaged	O
in	O
pursuing	O
this	O
concept	O
.	O
</s>
<s>
Various	O
on-chip	O
connection	O
schemes	O
of	O
microLED	B-General_Concept
pixel	B-Algorithm
arrays	O
have	O
been	O
employed	O
by	O
AC	O
LED	O
Lighting	O
,	O
LLC	O
(	O
a	O
company	O
funded	O
by	O
Hongxing	O
Jiang	O
and	O
Jingyu	O
Lin	O
)	O
allowing	O
for	O
the	O
development	O
of	O
single-chip	O
high	O
voltage	O
DC/AC	O
-LEDs	O
to	O
address	O
the	O
compatibility	O
issue	O
between	O
the	O
high	O
voltage	O
electrical	O
infrastructure	O
and	O
low	O
voltage	O
operation	O
nature	O
of	O
LEDs	O
and	O
high	O
brightness	O
self-emissive	O
microdisplays	O
.	O
</s>
<s>
The	O
microLED	B-General_Concept
array	O
has	O
also	O
been	O
explored	O
as	O
a	O
light	O
source	O
for	O
optogenetics	O
applications	O
and	O
for	O
visible	O
light	O
communications	O
.	O
</s>
<s>
Early	O
InGaN	O
based	O
microLED	B-General_Concept
arrays	O
and	O
microdisplays	O
were	O
primarily	O
passively	O
driven	O
.	O
</s>
<s>
The	O
first	O
actively	O
driven	O
video-capable	O
self-emissive	O
InGaN	O
microLED	B-General_Concept
microdisplay	O
in	O
VGA	O
format	O
(	O
pixels	B-Algorithm
,	O
each	O
12µm	O
in	O
size	O
with	O
15µm	O
between	O
them	O
)	O
possessing	O
low	O
voltage	O
requirements	O
was	O
patented	O
and	O
realized	O
in	O
2009	O
by	O
Hongxing	O
Jiang	O
and	O
Jingyu	O
Lin	O
and	O
their	O
colleagues	O
at	O
III-N	O
Technology	O
,	O
Inc	O
.	O
(	O
a	O
company	O
funded	O
by	O
Hongxing	O
Jiang	O
and	O
Jingyu	O
Lin	O
)	O
and	O
Texas	O
Tech	O
University	O
,	O
via	O
heterogeneous	O
integration	O
between	O
microLED	B-General_Concept
array	O
and	O
CMOS	O
integrated	O
circuit	O
(	O
IC	O
)	O
and	O
the	O
work	O
was	O
also	O
published	O
in	O
the	O
following	O
years	O
.	O
</s>
<s>
The	O
first	O
microLED	B-General_Concept
products	O
were	O
demonstrated	O
by	O
Sony	O
in	O
2012	O
.	O
</s>
<s>
There	O
are	O
several	O
methods	O
to	O
manufacture	O
microLED	B-General_Concept
displays	O
.	O
</s>
<s>
The	O
flip-chip	O
method	O
is	O
used	O
for	O
micro	O
displays	O
used	O
on	O
virtual	B-Device
reality	I-Device
headsets	I-Device
.	O
</s>
<s>
The	O
drawbacks	O
include	O
cost	O
,	O
limited	O
pixel	B-Algorithm
size	O
,	O
limited	O
placement	O
accuracy	O
,	O
and	O
the	O
need	O
for	O
cooling	O
to	O
prevent	O
the	O
display	O
from	O
warping	O
and	O
breaking	O
due	O
to	O
thermal	O
mismatch	O
between	O
the	O
LEDs	O
and	O
the	O
silicon	O
.	O
</s>
<s>
Also	O
,	O
current	O
microLED	B-General_Concept
displays	O
are	O
less	O
efficient	O
than	O
comparable	O
OLED	B-Device
displays	I-Device
.	O
</s>
<s>
Another	O
microLED	B-General_Concept
manufacturing	O
method	O
involves	O
bonding	O
the	O
LEDs	O
to	O
an	O
IC	O
layer	O
on	O
a	O
silicon	O
substrate	O
and	O
then	O
removing	O
the	O
LED	O
bonding	O
material	O
using	O
conventional	O
semiconductor	O
manufacturing	O
techniques	O
.	O
</s>
<s>
Quantum	O
dots	O
are	O
being	O
researched	O
as	O
a	O
way	O
to	O
shrink	O
the	O
size	O
of	O
microLED	B-General_Concept
pixels	B-Algorithm
,	O
while	O
other	O
companies	O
are	O
exploring	O
the	O
use	O
of	O
phosphors	O
and	O
quantum	O
dots	O
to	O
eliminate	O
the	O
need	O
for	O
different-colored	O
LEDs	O
.	O
</s>
<s>
Sensors	O
can	O
be	O
embedded	O
in	O
microLED	B-General_Concept
displays	O
.	O
</s>
<s>
Over	O
130	O
companies	O
are	O
involved	O
in	O
microLED	B-General_Concept
research	O
and	O
development	O
.	O
</s>
<s>
MicroLED	B-General_Concept
light	O
panels	O
are	O
also	O
being	O
made	O
,	O
and	O
are	O
an	O
alternative	O
to	O
conventional	O
OLED	B-Device
and	O
LED	O
light	O
panels	O
.	O
</s>
<s>
Digital	O
pulse-width	B-Algorithm
modulation	I-Algorithm
is	O
well-suited	O
to	O
driving	O
microLED	B-General_Concept
displays	O
.	O
</s>
<s>
MicroLEDs	B-General_Concept
experience	O
a	O
color	O
shift	O
as	O
the	O
current	O
magnitude	O
changes	O
.	O
</s>
<s>
Current	O
microLED	B-General_Concept
display	O
offerings	O
by	O
Samsung	B-Application
and	O
Sony	O
consist	O
of	O
"	O
cabinets	O
"	O
that	O
can	O
be	O
tiled	O
to	O
create	O
a	O
large	O
display	O
of	O
any	O
size	O
,	O
with	O
the	O
display	O
's	O
resolution	O
increasing	O
with	O
size	O
.	O
</s>
<s>
microLEDs	B-General_Concept
have	O
innate	O
potential	O
performance	O
advantages	O
over	O
LCD	B-Device
displays	I-Device
,	O
including	O
higher	O
brightness	O
,	O
lower	O
latency	O
,	O
higher	O
contrast	O
ratio	O
,	O
greater	O
color	O
saturation	O
,	O
intrinsic	O
self-illumination	O
,	O
and	O
better	O
efficiency	O
.	O
</s>
<s>
As	O
of	O
2016	O
,	O
a	O
number	O
of	O
different	O
technologies	O
were	O
under	O
active	O
research	O
for	O
the	O
assembling	O
of	O
individual	O
LED	O
pixels	B-Algorithm
on	O
a	O
substrate	O
.	O
</s>
<s>
These	O
include	O
chip	O
bonding	O
of	O
microLED	B-General_Concept
chips	O
onto	O
a	O
substrate	O
(	O
considered	O
to	O
have	O
potential	O
for	O
large	O
displays	O
)	O
,	O
wafer	O
production	O
methods	O
using	O
etching	O
to	O
produce	O
an	O
LED	O
array	O
followed	O
by	O
bonding	O
to	O
an	O
IC	O
,	O
and	O
wafer	O
production	O
methods	O
using	O
an	O
intermediate	O
temporary	O
thin	O
film	O
to	O
transfer	O
the	O
LED	O
array	O
to	O
a	O
substrate	O
.	O
</s>
<s>
Glo	O
and	O
Jasper	O
Display	O
Corporation	O
demonstrated	O
the	O
world	O
's	O
first	O
RGB	O
microLED	B-General_Concept
microdisplay	O
,	O
measuring	O
diagonally	O
,	O
at	O
SID	O
Display	O
Week	O
2017	O
.	O
</s>
<s>
Glo	O
transferred	O
their	O
microLEDs	B-General_Concept
to	O
the	O
Jasper	O
Display	O
backplane	O
.	O
</s>
<s>
Samsung	B-Application
demonstrated	O
a	O
microLED	B-General_Concept
display	O
called	O
The	O
Wall	O
at	O
CES	O
2018	O
.	O
</s>
<s>
In	O
July	O
2018	O
,	O
Samsung	B-Application
announced	O
plans	O
on	O
bringing	O
a	O
4K	O
microLED	B-General_Concept
TV	O
to	O
consumer	O
market	O
in	O
2019	O
.	O
</s>
<s>
At	O
CES	O
2019	O
,	O
Samsung	B-Application
demonstrated	O
a	O
4K	O
microLED	B-General_Concept
display	O
and	O
6K	O
microLED	B-General_Concept
display	O
.	O
</s>
<s>
On	O
June	O
12	O
at	O
InfoComm	O
2019	O
,	O
Samsung	B-Application
announced	O
the	O
global	O
launch	O
of	O
The	O
Wall	O
Luxury	O
microLED	B-General_Concept
display	O
configurable	O
from	O
in	O
2K	O
to	O
in	O
8K	O
.	O
</s>
<s>
On	O
October	O
4	O
,	O
2019	O
,	O
Samsung	B-Application
announced	O
that	O
The	O
Wall	O
Luxury	O
microLED	B-General_Concept
display	O
shipments	O
had	O
begun	O
.	O
</s>
<s>
In	O
March	O
2018	O
,	O
Bloomberg	O
reported	O
Apple	O
to	O
have	O
about	O
300	O
engineers	O
devoted	O
to	O
in-house	O
development	O
of	O
microLED	B-General_Concept
screens	O
.	O
</s>
<s>
At	O
IFA	O
2018	O
in	O
August	O
,	O
LG	O
Display	O
demonstrated	O
a	O
microLED	B-General_Concept
display	O
.	O
</s>
<s>
At	O
SID	O
's	O
Display	O
Week	O
2019	O
in	O
May	O
,	O
Tianma	O
and	O
PlayNitride	O
demonstrated	O
their	O
co-developed	O
microLED	B-General_Concept
display	O
with	O
over	O
60%	O
transparency	O
.	O
</s>
<s>
China	O
Star	O
Optoelectronics	O
Technology	O
(	O
CSoT	O
)	O
demonstrated	O
a	O
transparent	B-Device
microLED	B-General_Concept
display	O
with	O
around	O
45%	O
transparency	O
,	O
also	O
co-developed	O
with	O
PlayNitride	O
.	O
</s>
<s>
Plessey	O
Semiconductors	O
Ltd	O
demonstrated	O
a	O
monolithic	O
monochrome	O
blue	O
GaN-on-silicon	O
wafer	O
bonded	O
to	O
a	O
Jasper	O
Display	O
CMOS	O
backplane	O
active-matrix	O
microLED	B-General_Concept
display	O
with	O
an	O
8μm	O
pixel	B-Algorithm
pitch	O
.	O
</s>
<s>
At	O
SID	O
's	O
Display	O
Week	O
2019	O
in	O
May	O
,	O
Jade	O
Bird	O
Display	O
demonstrated	O
their	O
720p	O
and	O
1080p	O
microLED	B-General_Concept
microdisplays	O
with	O
5μm	O
and	O
2.5μm	O
pitch	O
respectively	O
,	O
achieving	O
luminance	O
in	O
the	O
millions	O
of	O
candelas	O
per	O
square	O
metre	O
.	O
</s>
<s>
At	O
Touch	O
Taiwan	O
2019	O
on	O
September	O
4	O
,	O
2019	O
,	O
AU	O
Optronics	O
demonstrated	O
a	O
microLED	B-General_Concept
display	O
and	O
indicated	O
that	O
microLED	B-General_Concept
was	O
12	O
years	O
from	O
mass	O
commercialization	O
.	O
</s>
<s>
At	O
IFA	O
2019	O
on	O
September	O
13	O
,	O
2019	O
,	O
TCL	O
Corporation	O
demonstrated	O
their	O
Cinema	O
Wall	O
featuring	O
a	O
4K	O
microLED	B-General_Concept
display	O
with	O
maximum	O
brightness	O
of	O
1,500	O
cd/m	O
and	O
contrast	O
ratio	O
produced	O
by	O
their	O
subsidiary	O
China	O
Star	O
Optoelectronics	O
Technology	O
(	O
CSoT	O
)	O
.	O
</s>
<s>
According	O
to	O
a	O
report	O
by	O
Bloomberg	O
,	O
Apple	O
is	O
working	O
on	O
its	O
own	O
in-house	O
design	O
of	O
MicroLED	B-General_Concept
displays	O
.	O
</s>
<s>
The	O
introduction	O
of	O
these	O
displays	O
will	O
end	O
Apple	O
's	O
dependence	O
on	O
Samsung	B-Application
,	O
LG	O
and	O
other	O
display	O
manufacturers	O
,	O
and	O
is	O
in	O
line	O
with	O
the	O
company	O
's	O
other	O
steps	O
towards	O
complete	O
vertical	O
integration	O
.	O
</s>
<s>
The	O
transition	O
to	O
MicroLED	B-General_Concept
will	O
begin	O
with	O
the	O
Apple	B-Device
Watch	I-Device
,	O
with	O
the	O
first	O
MicroLED	B-General_Concept
watches	O
potentially	O
entering	O
the	O
market	O
in	O
2024	O
or	O
2025	O
.	O
</s>
