With today's digital cameras, you can easily take 3 Megapixel digital images
-- but 5, 6 or 12 Megapixel cameras are not un-usual. With display technologies
maturing, prices dropping, resolution increasing and sensor sensitivity
increasing -- what display to buy no longer has a simple answer -- other than it
depends on your intended purpose and your budget.
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I want a Desktop Monitor
I want something cheap but good: In many ways CRTs offer excellent color
depth, resolution and contrast at a very affordable price. Yet the tradeoff is
clear -- you need a ton of space in order to be able to put one on your desk and
they weigh a ton. Given that however, these monitors can have resolutions up to
2580x1920 feedable straight from a single output video card and for the low price
are a tremendous bargain. You can buy a new one ranging price from 150 dollars
for a 19" system that displays up to 1600x1200 weighs a mere 50 lbs and with an
18" width, 18" height, and 18" depth. La Cie Makes one with very good color
calibration. If you are trying to do image editing ,these systems offer excellent
value and are much better than almost anything else you can buy. The blacks are
blacker, the contrast is great, though there can be some convergence and burnin
issues one should be careful about.
I want a flat screen.
Active Matrix LCD is the way to go. These screens are reasonably bright 250 to
500 Nits is good. The DVI standard has emerged as the way to drive these
displays. And they range in size from 15" to 32"(for desktop). The price is all
over the board ranging from 200 for a 14.1" VGA to 8000 dollars for a 32" system.
This is the way to go if you don't have space and also want nice clean images.
I want the most pixels money can buy for a desktop.
For some of you, 2 megapixel just isn't enough. We understand. You'll have
problems to get a display as large as a plasma display. But, resolution is
obtainable in smaller sizes. There are two solution of which we are aware. IBM
has been selling its T221 Display and similar so has view sonic. These are 9
megapixel displays. Unfortunately they are only 23.1" in size but do provide
about 200 DPI. For those of you seeking more there are several approaches to
tiling displays to get what you want but it is a custom business that is very
expensive even if you buy a video wall with seams.
I want a Large Screen
There are a number of options for Large Screen Displays- Bigger than 32":
Plasma Displays and LCD Displays of this size are strikingly beautiful but very
expensive. More affordable alternatives are lower end front projectors and rear
projection TVs. Unfortunately at these sizes resolution is not easily attainable.
So if you are looking to make a 50" electronic display frame to show your scanned
in Medium format images in all their glory -- the single display large screen is
not quite there yet. (though a CRT display can often do up to 4-5 megapixels) But
there are ways to do that but they are very expensive. In considering what to buy
it is probably best to break this up by the intended use. Given that Home theater
systems are more likely to provide the best color -- they are probably the best
set of projectors to consider for showing your works. For Home Theater it is
important to be able to have a 16x9 ratio image for showing digital theater. The
industry is changing to 1080P HDTV content and similarly the technology available
today is just starting to be able to deliver 1980x1080 content. Also Color is a
big deal as well. At the very highest end people talk about brightness but to
watch movies like they were intended to be watched one wants a system that can
reproduce a D65 color temperature white point. Below we go through what you can
get for different price ranges.
| 500 dollars you can buy 800x600 |
| 1000 dollars you can buy a 42" 16x9 television 480P or a 800x600
projector. |
| 2000 dollars you can buy a very reasonable projection system or RPTV. |
| 4000 dollars you can buy a plasma display. |
| 9000 dollars you can start buying top of the line projector like the infocus
Screen Play 7205 or an LCOS RPTV from Brillian might interest you. |
| 30000 Try the Sony Qualia |
| 40000 Runco |
| 150,000 Consider the three digital cinema projectors from DPI,Barco and
Christie Digital -- 2k and between 20000 and 30000 Lumens. Runco Also offers a
projector and while not as bright provides good input. |
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Psychology of Perceived Quality
Psychological studies indicate that humans respond to brightness more than
anything else when looking at images. Contrast, the ratio of white to black tends
to come in second. Though notably for photography this can arguably be just as
important in that exposure of an image is best shown on a display capable of high
contrast. The importance of contrast is generally determined by your background
lighting. In a bright consumer electronic store there is a *lot* of background
lighting so that the background lighting of the display is unimportant in
comparison to the background light in the television/monitor. In your living
room, contrast will generally be important (unless the sun is shining on the
display). Thus, if you want to see the darkest levels in your photos, you want a
high-contrast display. Finally one should consider that sensors color depth is
also rising and that if you are getting 12 bits per color like you might get from
a film scan then you need a monitor that can display that color in order to get
the full benefit of the data. For digital cinema for example this is considered a
requirement.
Technologies To Consider
CRT
In many ways the CRT (Cathode Ray Tube) display is dying. In a few years, it
will start to get difficult to buy big, heavy, clunky monitors and TVs. The flats
screens will replace them. Nonetheless this is probably the most mature
technology there is available to reproduce dynamic images on a display -- it
offers the blackest blacks and best contrast at the best price.
Liquid Crystal Displays (LCD)
Liquid crystals rotate the polarization of light going through them. However,
they lose this property when a voltage is applied across them. So, if one put a
well-chosen liquid crystal layer in between crossed polarizers, the light that
passed through the first polarizer would not pass through the second. If one then
applied a certain voltage to the liquid, the light would pass. Thus an Liquid
Crystal Display (LCD) is just lots of little dots consisting of cross-polarizer,
and liquid crystals.
LCD displays make up the majority of your computer-monitor, flat screen
displays. And, they make up a large range of flat screen televisions. By using a
bright light source, LCDs are known for making displays that can be very bright.
However, when attempting to display black, LCD displays are not very good; some
light makes it through when the LCDs try to block light. The contrast ratio
(ratio of white to black) is often about 300. For comparison, plasma displays
have contrast ratios of 1000.
Samsung (www.samsung.com) is the big investor in these technologies. They are
about to build a 3 billion dollar fabrication facility, that will make mostly 50
and 60 inch televisions, among other applications. Watch for much less expensive
LCD televisions them by 2007.
Plasma
The big competitor to LCD is plasma displays. Plasma displays are based on
little pockets of gas that are excited and give off light. Plasma displays have a
much higher contrast ratio than LCDs. However, these displays are not as bright.
And, they can be very expensive.
Thick Film Transistor
Thick Film electroluminescent technology is coming. Ifire (ifire.com) is
working on this film transistors that give off light when voltages are applied.
This technology is a few years away from production. But, it promises much
cheaper technology than LCD or Plasma for sizes small then 30 or 40 inches. It
will probably be 3 years before you can buy one of these displays.
Back Projection
A cheaper alternative to LCD and plasma displays are back projection displays.
These displays bounce light off a micro-display, and then onto a screen (The
coming sections are on micro-displays). These displays can be somewhat big and
clunky, unlike the flat plasma and LCD displays. Worse, they tend to have lower
brightness and lower contrast ratio than both Plasma and LCD plat panel
displays.
Digital Micro Mirror
Texas Instruments made a small chip that consists of millions of tiny mirrors.
Light incident on the mirrors is either directed towards the target or towards an
absorber. These micro-displays tend to have high contrast ratios. But, they tend
to be more expensive than other back-projection solution like LCOS. However that
said they are probably the dominant player now for both rear and back
projector.
Liquid Crystal on Silicon (LCOS)
One up and coming technology is LCOS. LCOS is nothing more than liquid
crystals on top of silicon. This technology is up and coming, and you'll start to
see back-projection televisions made from these in the coming years. Brillian,
for example, claims to have one coming out in August. They make claims of
contrast ratios higher than LCD. We'll see if that is true after they come out.
JVC has done this for years and provides a technology called DILA -- meanwhile
the most sophisticated offering out there for cheap projectors will come from
philips and microdisplay corporation who offer single panel LCOS solutions much
like TI. Sony also has implemented this technology and has several high end
projectors using it.
High Temperature Poly Silicon:
This is the technology to replace -- seiko epson, sony, sanyo all ship this
technology and it is cheap though lacks the contrast that the dmd mirrors provide
and that LCOS promises. So this is likely to get displaced by LCOS.
Forward Projection
Why not use the same projector you use in your conference room as your
television? The problem has been that the screens scatter ambient light into your
eye so that effective contrast ratios have been very low. However, Sony has a new
screen that does not seem to scatter ambient light. It's quite an amazing screen.
When it comes on the market; I expect it will become very popular, very quickly.
(Sony did not say when they they will start selling it.)
Which is better?
It is very hard to tell which type of display is better by looking at the
marketing material put out by the display industry. This is mostly because the
information in marketing materials is generally inaccurate. As an extreme
example, at the recent Society for Information Display (SID) meeting in Seattle,
Larry Weber claimed to have tested LCD televisions and found that their
brightness collapsed after a few hundreds hours, not the many thousands that the
manufacturers claimed.
Furthermore, the lighting in a typical store is much brighter than the
lighting in your home. Thus, the picture on that expensive television you buy
will look very different in your living room than it did in the show room. Said
differently, the black on an LCD won't look any better when you take it home. The
black on a plasma display will look much better.
Back projection displays are often less bright and lower contrast than LCD and
Plasma displays. But, they are much, much less expensive.
The resolution to keep in mind is 1920x1080 which is the new resolution for HD
TV. Pretty much all of the technologies will be able to produce the new
resolution; and it will start to be commonly available in the fall of 2004. (The
exception is DMD, which I do not believe is being made in that resolution.) For
high resolution, the only choice right now is LCD. There are already 5 and 7
megapixel displays using LCD technologies (IBM and NEC are making such displays).
LCOS projection system will likely get up to 8 megapixel in a few years.
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