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The
advantage of DLP is two-fold:
* It produces bright, high-contrast images,
viewable from a wide angle, and (2) It can
be projected onto any size screen (from
home theater setups to movie theater setups),
with equal image quality; and
* With the advent of HDTV, DLP is the best
option for reproducing high-resolution projected
images.
On
the industrial front, DLP is being used
in large projection screen applications
such as concert venues and movie theaters.
Several
films have been released to special take
advantage of DLP projection technology,
including: Star Wars: Episode I, Mission
To Mars, Toy Story 2, Rocky and Bullwinkle,
Disney's Dinosaur, and Spy Kids.
In
a recent BBC feature on its technology programme,
Click, it said that domestic video projectors
come in two different flavours: LCD or DLP.
The
brainchild of Texas Instruments, Digital
Light Processing (DLP) first appeared 20
years ago. In video projectors the key to
DLP are optical semiconductors covered in
millions of tiny mirrors.
These
mirrors reflect light which is projected
onto them, and each mirror represents an
individual pixel. The higher the resolution
the more mirrors are required.
Bob
Johnson of Optoma told BBC's Click on April
16: "It's a digital device, whereas
the majority of the other technologies are
all analogue devices. So if you're using
an HD DVD player or your normal home DVD
player, that's a digital device, you get
a digital image on your screen."
There
is one drawback to DLP technology.
In
order for the chips to produce colour images,
a spinning wheel fitted with coloured filters
is placed in front of the chip. When this
wheel spins it can create an effect which
looks like rainbow patterns appearing around
the pixels. This can be a bit irritating.
LCD
projectors don't enjoy the same level of
contrast or dark blacks that DLPs produce,
and up close some individual pixels can
be visible as squares. There is however
a price difference - many LCD projectors
are cheaper than their DLP counterparts.
Improvements
in lamp technology mean that a wide variety
of the bulbs that are fitted to the current
generation of video projectors are so bright
they can viewed in almost daylight conditions.
And
as LCD screens have embraced HD 1080P resolution
so to have video projectors. So it's possible
to use projectors in rooms that aren't as
dark as your local multiplex - and with
HD support, movies, TV and video games now
look pin sharp.
But
if you're planning to ditch the TV in favour
of a projector what sort of features should
you be looking out for?
Picture
size is altered by the distance the projector
is away from the screen, known as 'throw'.
As a rule of thumb about 10ft away from
a wall or a screen will produce an image
of 100 inches.
It's
important to select a projector and bulb
which can produce a sufficient amount of
light to work in a domestic setting. Known
as the lumen value, this allows you to know
how bright a bulb is. For a room which has
ambient lighting in it a bulb which produces
in excess of 1200 lumens will be required.
Projectors
used to make more noise than a normal TV
due to fans that are needed to cool the
unit down. Although modern projectors are
considerably quieter than their forebears,
fan noise is still evident.
The
biggest drawback is the cost of replacement
lamps. Lamps usually last around 2000 to
3000 hours, but after that it's time for
a new one and this can be expensive, in
some cases up to £400. But overall
prices of domestic projectors have dropped.
It's possible to get a DLP HD -ready projector
for around £700, which compares favourably
with large LCD or Plasma screens.
Great
big video projectors are fine if you've
got a great big home to put them in, but
if there's a shortage of space a tiny little
DLP projector can provide a solution to
the problem.
And
as laser technology becomes introduced to
projectors they are going to get even smaller.
There
is a company in the United States that's
developing a projector which is so small
it will fit inside a mobile phone.
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