Hello Mao,
So, let?s talk about projectors.
There are two main kinds LCD and DLP.
LCD projectors stand for liquid crystal display. They usually contain
three separate class panels (red, green, and blue)
DLP is Digital Light Processing. It has a single chip made up of many
tiny mirrors that represent each pixel. There is a color wheel that
consists of red, green, and blue at minimum. ?In a DLP projector,
light from the projector's lamp is directed onto the surface of the
DLP chip. The mirrors wobble back and forth, directing light either
into the lens path to turn the pixel on, or away from the lens path to
turn it off.?
Depending on the quality of the color, LCD has a small advantage over
DLP. DLP sometimes is brighter, reducing the appearance of the picture
because the color saturation is reduced. If you find a DLP with more
color segments on the wheel this improves the quality of the picture.
LCD can be sharper; however, this comes into play with more detailed
applications like computer information being projected. It?s not as
noticeable in video. LCD also has an advantage in the fact it?s more
light efficient.
However, LCD also has its disadvantages.
?The first is visible pixelation--the ability to see the discrete
pixels on the screen. The second is commonly referred to as the
"screendoor effect" because it looks like you are viewing the image
through a screendoor. The screendoor effect is caused by the space
between the pixels, known as the inter-pixel gap. The third weakness
is not-so-impressive black levels and contrast, which are vitally
important elements in a good video image. LCD technology has in the
past had a hard time being taken seriously among some home theater
enthusiasts (understandably) because of these flaws in the image.?
However, as time has passed, this has gotten a lot better.
DLP has an advantage over LCD in contrast as well. If you plan to
watch the projector in a dark setting, this is important. In a
partially lighted room however, contrast drops sharply anyway, so it
might not be as big as a concern for you then.
DLP is usually more compact than LCD as well. Depending if size is
important to you, this may be a factor as well.
LCD projectors also may suffer from some color degradation over time
as well as opposed to LCD. However, DLP with one chip may have you
noticing the color changes (some people?s eyes can detect this) and it
may cause headaches while viewing. This is not very common, but if you
have sensitive eyes to things like this, it may put the LCD at an
advantage.
?However there is no way for you to know if you or another regular
user are among those that may be bothered by ill-effects from the
spinning color wheel without sitting down and viewing a DLP projector
for a while.?
http://www.projectorcentral.com/lcd_dlp_update6.htm (LCD vs. DLP)
------------------------------------------------------------------------------------
As far as resolution goes, you have a number of options.
?Most people looking for home theater projectors want to go with the
widescreen, 16:9 format that is the native format for HDTV. There are
three popular 16:9 resolution formats now. The first is 854x480, the
second is 1024x576, and the third is 1280x720. Since these are all
progressive scan displays, they are designated as 480p, 576p, and 720p
resolutions, respectively.?
Now, since most DVD?s are scaled at 480p, increasing the resolution on
a projector can go two ways. One way is that it scales it great and
life goes on. The other is that it softens the picture once it?s
scaled.
However, if you want it to be NDTV compatible, it may be better to get
a higher resolution projector.
?Second, there is the possibility of getting a slightly better HDTV
picture. That is because the HD signal, which is either 1920x1080 or
1280x720, is being compressed into an array of 1024x576 rather than
the lower resolution 854x480 array. Since the 576p model has more
pixels, it has the potential to retain a bit more detail in the HDTV
image.?
?The basic question then is this: Do you want to lay out more money to
gain subtle improvements in pixelation and HDTV acuity, while
compromising the sharpness of your DVD picture? Most people would
think this is a dubious trade-off. Yet this is the value proposition
being offered by the 1024x576 resolution projectors in the NTSC world.
On the other hand, everything changes if you live in a country where
PAL or SECAM is the video standard. These systems deliver 576 lines of
video per frame, rather than the 480 lines per frame of NTSC. So in
this environment, the 1024x576 resolution projector is the ideal
solution for DVD and standard definition video.?
I?d personally recommend a 480p if you are going to be watching DVD?s
and HDTV. It?s the best bet for your money, as long as you?re not
completely obsessed with having the BEST home theater in the
neighborhood. If you are THAT concerned and your focus is mostly HDTV,
go with the 720p or higher.
http://www.projectorcentral.com/choosing_resolution.htm (resolution)
------------------------------------------------------------------------------------
Now, let?s talk about TRUE HDTV.
?There are two common HDTV formats in use today, usually referred to
as 1080i and 720p. The numbers refer to the number of horizontal lines
in each frame of video (also known as "vertical resolution" since it
is the number of horizontal lines as counted vertically from top to
bottom of the screen). So in a 1080i signal, there are 1,080 lines per
frame of video, and in a 720p signal there are 720 lines per frame.?
While this may not be a huge deal, I recommend reading this article
about TRUE HDTV before you go to purchase.
http://www.projectorcentral.com/true_hdtv.htm
------------------------------------------------------------------------------------
Replacement Lamps, etc.
Lamps typically last about 2000 hours of viewing time, and cost about
$300-450.00 to replace. You also need to clean the air filter on your
projector every 2 months or so. Some laps now offer 3000 or 5000
hours.
You may want to think about lamp life depending on how often the
projector may be on.
------------------------------------------------------------------------------------
We mentioned earlier about widescreen being a 16:9 ratio. Regular TV
is a 4:3 ratio. You have to decide which one you would like better.
Most home theaters go with the 16:9 ratio. HDTV is a 16:9 ratio, as
are most DVD?s. Regular TV is a 4:3 ratio and may stretch out the
picture. Depending if HDTV and DVD?s are your focus, or just watching
it like the normal TV is the deciding factor of your aspect ratio. A
16:9 can display 4:3 but the image may be compromised some. Most older
movies are in 4:3 and many music videos are 4:3 as opposed to 16:9.
Many TV shows on DVD are 4:3 as well.
?With a 16:9 projector, one option is to display 4:3 material in its
correct aspect ratio using the middle two-thirds of the screen. When
you do this you will have black pillars or columns on each side of the
image that fill the space between the image and the sides of your
screen.
Another option, not so appealing, is to use the "expand" feature on
the projector which stretches the 4:3 image horizontally so it fills
the 16:9 frame. In this mode people will appear fatter. Cars look like
low-riders on oval shaped tires. Yes, it fills the 16:9 screen, but
the romantic essence of Casablanca, a 4:3 film, is somewhat
compromised when you make Bogart and Bergman look like they've spent
the war years gorging on French cheese and pate. To anyone serious
about seeing a classic film the way the director created it, this
tasteless distortion of the 4:3 image (a "featured option" of all 16:9
video display devices) will be unacceptable.?
http://www.projectorcentral.com/formats.htm (About aspect ratio)
------------------------------------------------------------------------------------
LCOS ? another kind of display like LCD and DLP that we haven?t
mentioned yet. LCOS stands for Liquid Crystal on Silicon.
?What is LCOS technology?
Well, you could think of it as a hybrid between LCD and DLP. LCD uses
liquid crystals, one for each pixel, on glass panels. Light passes
through these LCD panels on the way to the lens and is modulated by
the liquid crystals as it passes. Thus it is a "transmissive"
technology. On the other hand, DLP uses tiny mirrors, one for each
pixel, to reflect light. DLP modulates the image by tilting the
mirrors either into or away from the lens path. It is therefore a
"reflective" technology.
LCOS combines these two ideas. It is a reflective technology that uses
liquid crystals instead of individual mirrors. In LCOS, liquid
crystals are applied to a reflective mirror substrate. As the liquid
crystals open and close, the light is either reflected from the mirror
below, or blocked. This modulates the light and creates the image.
http://www.projectorcentral.com/lcos.htm
These projectors are quite expensive. I would not recommend them for a
typical home user.
------------------------------------------------------------------------------------
More information from Projector Central http://www.projectorcentral.com/
------------------------------------------------------------------------------------
I think the best decision here is your own. If it?s just for typical
watching, go with LCD. If you?re quite serious about quality and
image, go with DLP. I would go with the 16:9 aspect ratio if you?re
more into DVD?s and HDTV, the 4:3 if all you watch is normal TV. If
you?re in America, go with a 480p if you?re in another country, go 1
step up due to the fact countries other than America broadcast at a
higher resolution. If you want it to be a high-end system, go with
780p. It all depends on how much you want to spend in the end for what
quality. I?d try to find a longer life bulb and check to see if the
warranty covers any bulb replacement.
You can do a google search for these terms if you?d like to see consumer reviews.
LCD projector reviews
DLP projector reviews
Google Search:
Information on projectors
://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=information%20on%20projectors&btnG=Google+Search
If this answer requires further explanation, please request
clarification before rating it, and I'll be happy to look into this
further.
Nenna-GA
Google Answers Researcher |
