<s>
A	O
video	B-Device
projector	I-Device
is	O
an	O
image	B-Application
projector	I-Application
that	O
receives	O
a	O
video	O
signal	O
and	O
projects	O
the	O
corresponding	O
image	O
on	O
a	O
projection	O
screen	O
using	O
a	O
lens	O
system	O
.	O
</s>
<s>
Video	B-Device
projectors	I-Device
use	O
a	O
very	O
bright	O
ultra-high-performance	O
lamp	O
(	O
a	O
special	O
mercury	O
arc	O
lamp	O
)	O
,	O
Xenon	O
arc	O
lamp	O
,	O
LED	O
or	O
solid	O
state	O
blue	O
,	O
RB	O
,	O
RGB	O
or	O
remote	O
fiber	O
optic	O
RGB	O
lasers	O
to	O
provide	O
the	O
illumination	O
required	O
to	O
project	O
the	O
image	O
,	O
and	O
most	O
modern	O
ones	O
can	O
correct	O
any	O
curves	O
,	O
blurriness	O
,	O
and	O
other	O
inconsistencies	O
through	O
manual	O
settings	O
.	O
</s>
<s>
Remote	O
fiber	O
optic	O
RGB	O
laser	O
racks	O
can	O
be	O
placed	O
far	O
away	O
from	O
the	O
projector	B-Application
,	O
and	O
several	O
racks	O
can	O
be	O
housed	O
in	O
a	O
single	O
,	O
central	O
room	O
.	O
</s>
<s>
Each	O
projector	B-Application
can	O
use	O
up	O
to	O
two	O
racks	O
,	O
and	O
several	O
monochrome	O
lasers	O
are	O
mounted	O
on	O
each	O
rack	O
,	O
the	O
light	O
of	O
which	O
is	O
mixed	O
and	O
transmitted	O
to	O
the	O
projector	B-Application
booth	O
using	O
optical	O
fibers	O
.	O
</s>
<s>
Projectors	B-Application
using	O
RB	O
lasers	O
use	O
a	O
blue	O
laser	O
with	O
a	O
phosphor	O
wheel	O
in	O
conjunction	O
with	O
a	O
conventional	O
solid	O
state	O
red	O
laser	O
.	O
</s>
<s>
Video	B-Device
projectors	I-Device
are	O
used	O
for	O
many	O
applications	O
such	O
as	O
conference	O
room	O
presentations	O
,	O
classroom	O
training	O
,	O
home	O
cinema	O
,	O
movie	O
theaters	O
and	O
concerts	O
,	O
having	O
mostly	O
replaced	O
overhead	B-Device
,	O
slide	B-Device
and	O
conventional	O
film	B-Application
projectors	I-Application
.	O
</s>
<s>
In	O
schools	O
and	O
other	O
educational	O
settings	O
,	O
they	O
are	O
sometimes	O
connected	O
to	O
an	O
interactive	B-Application
whiteboard	I-Application
.	O
</s>
<s>
Although	O
large	O
LCD	B-Device
television	O
screens	O
became	O
quite	O
popular	O
,	O
video	B-Device
projectors	I-Device
are	O
still	O
common	O
among	O
many	O
home	O
theater	O
enthusiasts	O
.	O
</s>
<s>
A	O
video	B-Device
projector	I-Device
,	O
also	O
known	O
as	O
a	O
digital	B-Device
projector	I-Device
,	O
may	O
project	O
onto	O
a	O
traditional	O
reflective	O
projection	O
screen	O
,	O
or	O
it	O
may	O
be	O
built	O
into	O
a	O
cabinet	O
with	O
a	O
translucent	O
rear-projection	O
screen	O
to	O
form	O
a	O
single	O
unified	O
display	O
device	O
.	O
</s>
<s>
The	O
cost	O
of	O
a	O
projector	B-Application
is	O
typically	O
driven	O
by	O
its	O
base	O
technology	O
,	O
features	O
,	O
resolution	O
,	O
and	O
light	O
output	O
.	O
</s>
<s>
A	O
projector	B-Application
with	O
a	O
higher	O
light	O
output	O
(	O
measured	O
in	O
lumens	O
,	O
“	O
lm	O
”	O
)	O
is	O
required	O
for	O
a	O
larger	O
screen	O
or	O
for	O
a	O
room	O
with	O
a	O
larger	O
amount	O
of	O
ambient	O
light	O
.	O
</s>
<s>
A	O
few	O
camcorders	O
have	O
a	O
built-in	O
projector	B-Application
suitable	O
to	O
make	O
a	O
small	O
projection	O
;	O
a	O
few	O
more	O
powerful	O
"	O
pico	B-General_Concept
projectors	I-General_Concept
"	O
are	O
pocket-sized	O
,	O
and	O
many	O
projectors	B-Application
are	O
portable	O
.	O
</s>
<s>
LCD	B-Device
projector	I-Device
using	O
LCD	B-Device
light	O
gates	O
.	O
</s>
<s>
Common	O
problems	O
include	O
a	O
visible	O
“	B-General_Concept
screen	I-General_Concept
door	I-General_Concept
”	I-General_Concept
or	I-General_Concept
pixelation	I-General_Concept
effect	I-General_Concept
,	O
and	O
the	O
LCD	B-Device
panels	I-Device
deteriorating	O
from	O
heat	O
&	O
UV	O
rays	O
,	O
leading	O
to	O
discolored	O
spots	O
or	O
holes	O
in	O
the	O
image	O
,	O
although	O
recent	O
advances	O
have	O
reduced	O
the	O
severity	O
of	O
these	O
issues	O
in	O
some	O
models	O
.	O
</s>
<s>
DLP	B-General_Concept
projector	I-General_Concept
using	O
Texas	O
Instruments’	O
DLP	B-General_Concept
technology	O
.	O
</s>
<s>
More	O
recent	O
projectors	B-Application
with	O
higher	O
speed	O
(	O
2x	O
or	O
4x	O
)	O
and	O
otherwise	O
optimised	O
color	O
wheels	O
have	O
lessened	O
this	O
effect	O
.	O
</s>
<s>
3-chip	O
DLP	B-General_Concept
projectors	I-General_Concept
do	O
not	O
have	O
this	O
problem	O
,	O
as	O
they	O
display	O
each	O
primary	O
color	O
simultaneously	O
,	O
and	O
offer	O
higher	O
light	O
output	O
and	O
more	O
accurate	O
color	O
reproduction	O
,	O
however	O
the	O
cost	O
is	O
significantly	O
higher	O
and	O
thus	O
3-chip	O
DLP	B-General_Concept
technology	O
is	O
typically	O
used	O
in	O
large	O
venue	O
,	O
high	O
brightness	O
models	O
,	O
as	O
well	O
as	O
Digital	O
Cinema	B-Application
projectors	I-Application
.	O
</s>
<s>
LCoS	B-Device
projectors	B-Application
(	O
liquid	B-Device
crystal	I-Device
on	I-Device
silicon	I-Device
)	O
.	O
</s>
<s>
Such	O
projectors	B-Application
often	O
process	O
light	O
in	O
the	O
Fourier	O
domain	O
,	O
which	O
enables	O
correction	O
of	O
optical	O
aberrations	O
using	O
Zernike	O
polynomials	O
.	O
</s>
<s>
D-ILA	B-Device
JVC	O
’s	O
Direct-drive	O
Image	O
Light	O
Amplifier	O
based	O
on	O
LCoS	B-Device
technology	O
.	O
</s>
<s>
SXRD	O
Sony	O
’s	O
proprietary	O
variant	O
of	O
LCoS	B-Device
technology	O
.	O
</s>
<s>
LED	O
projectors	B-Application
use	O
one	O
of	O
the	O
above-mentioned	O
technologies	O
for	O
image	O
creation	O
,	O
with	O
a	O
difference	O
that	O
they	O
use	O
an	O
array	O
of	O
Light	O
Emitting	O
Diodes	O
as	O
the	O
light	O
source	O
,	O
negating	O
the	O
need	O
for	O
lamp	O
replacement	O
.	O
</s>
<s>
Uses	O
a	O
combination	O
of	O
Light	O
Emitting	O
Diodes	O
and	O
445nm	O
laser	O
diodes	O
as	O
the	O
light	O
source	O
,	O
while	O
image	O
is	O
processed	O
with	O
DLP	B-General_Concept
(	O
DMD	O
)	O
chip	O
.	O
</s>
<s>
Laser	O
diode	O
projectors	B-Application
have	O
been	O
developed	O
by	O
Microvision	O
and	O
Aaxa	O
Technologies	O
.	O
</s>
<s>
Microvision	O
projectors	B-Application
use	O
Microvision	O
's	O
patented	O
MEMS	B-Architecture
laser	O
beam-steering	O
technology	O
,	O
whereas	O
Aaxa	O
Technologies	O
uses	O
laser	O
diodes	O
+	O
LCoS	B-Device
.	O
</s>
<s>
Laser	O
projectors	B-Application
are	O
now	O
available	O
from	O
most	O
projector	B-Application
manufacturers	O
,	O
including	O
Barco	O
,	O
Canon	O
,	O
Christie	O
Digital	O
,	O
Dell	O
,	O
Epson	O
,	O
Hitachi	O
,	O
NEC	O
,	O
Optoma	O
,	O
Panasonic	O
,	O
Sony	O
,	O
Viewsonic	O
and	O
many	O
others	O
.	O
</s>
<s>
These	O
units	O
use	O
a	O
laser	O
light	O
source	O
(	O
instead	O
of	O
conventional	O
lamps	O
)	O
,	O
and	O
are	O
used	O
with	O
most	O
common	O
projection	O
technologies	O
,	O
including	O
single	O
&	O
3-Chip	O
DLP	B-General_Concept
,	O
LCD	B-Device
and	O
LCoS	B-Device
.	O
</s>
<s>
Typical	O
laser	O
light	O
sources	O
used	O
in	O
projectors	B-Application
are	O
rated	O
for	O
20,000	O
hours	O
before	O
the	O
light	O
output	O
is	O
reduced	O
to	O
50%	O
,	O
whereas	O
lamps	O
lose	O
brightness	O
quickly	O
and	O
need	O
to	O
be	O
replaced	O
after	O
as	O
little	O
as	O
1000	O
–	O
2000	O
hours	O
.	O
</s>
<s>
CRT	B-General_Concept
projector	I-General_Concept
using	O
cathode	B-Device
ray	I-Device
tubes	I-Device
.	O
</s>
<s>
Some	O
hobbyists	O
build	O
a	O
do-it-yourself	O
(	O
DIY	O
)	O
projector	B-Application
for	O
low	O
cost	O
.	O
</s>
<s>
They	O
build	O
their	O
projectors	B-Application
from	O
kits	O
,	O
sourced	O
components	O
,	O
or	O
from	O
scratch	O
,	O
using	O
a	O
television	O
set	O
as	O
a	O
light	O
source	O
.	O
</s>
