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Hardware: LCD Monitors

LCD monitors, the thin ones you see replacing those big boxy CRT monitors, actually outsold CRTs in 2005 for the first time according to a few sources, and it's no wonder. They're brighter, clearer, easier to read, take up much less space on your desk and the big factor: came down in price significantly in recent years. A 17 inch LCD gives you about as much screen area as a 19" CRT because when a CRT is sold in Canada the size is measured before it is put into its case and part of the frame actually covers up the measured part of the screen. An LCD, on the other hand, is measured corner-to-corner as well, but what you measure is what you get.

LCD monitors are digital, but most have analog inputs, because that is what most people still have on their video cards in their PCs. Many LCD monitors also have a digital input jack which, if your PC supports it, should be the one you use. A PC, after-all creates a digital image which gets converted to analog, so you can view it, and then gets converted back to digital within the LCD monitor. Your colours will be truer, and you picture clearer, if you do not go through this conversion and drive the monitor digitally, if you can.

Lastly, if you are used to specifications for CRTs, because you've bought so many, some of the items below may be of interest. It explains some of the factors you may wish to be informed of before selecting a brand of LCD monitor. The references were collected over a year ago but the details are the same today. So, the words the salesman may try and bring to your attention, when shopping for an LCD monitor (and my comments on each) are:

The maximum viewing angle should be as wide as possible, ideally greater than or equal to 120° vertically (the horizontal angle isn't that important). Many are at least 160°.

The response time should be as short as possible. The current best is 25 ms. But watch out! Some manufacturers differentiate between the rise-up and fall-down times, i.e. the time required for each pixel to glow white, turn black and then revert to white again. By this measure, a monitor with a rise-up time of 15 ms and a fall-down time of 25 ms has a total response time of 40 ms.

The contrast and brightness should be as high as possible - at least higher than 300:1 and 200 cd/ mē, respectively.

Inputs can be important. Newer video cards have both Analog and Digital outputs. Some LCD monitors can take advantage of both. Accepting digital video means less degradation in quality as both computer files and LCD monitors are digital. Conversion to analog (and then back to digital) can cause information loss.

Dot pitch is a term adopted from CRT Monitors. Each dot on a Cathode Ray Tube Monitor is comprised of a Red, a Green and a Blue dot. This is known as a triad. The distance between each RGB triad is known as the dot pitch. The smaller the dot pitch, the better detail a monitor can display. LCD screens don't have triads. Each dot on the screen can display any colour. Therefore, technically, the term "dot pitch" is irrelevant. However, this term appears in most ads because it still reflects a value representing detail displayable by the monitor. Again, the lower the lot pitch the clearer the detail.

Tilt and swivel is available on some LCD's. Obviously this will be a more valuable feature to some than others. Height adjustment is another feature sometimes available.

Resolution refers to the maximum recommended display resolution of the monitor. In terms of LCD's however, it also refers to the recommended minimum display resolution. Anything other than the actual number of horizontal and vertical pixels of the screen has to be emulated and corrected with technology like anti-aliasing and is sometimes best avoided. CRT's have much more leeway with resolution.

Size is possibly the biggest factor determining the cost of the LCD monitor. A 15" LCD has about the same viewable screen size as a 17" CRT monitor because some of the screen measured on the CRT is covered by the housing. On an LCD every pixel is viewable.

Some Problems

The biggest downside to LCD screens is the fact that they may have one or more dead pixels. Fixing these white (TN + film) or black dots is not possible - which is a serious problem, since they can really be distracting. So before actually buying an LCD monitor, it's a good idea to find out how comprehensive a warranty your dealer offers - in other words, how many defective pixels do you need to have before you can trade in your monitor for a new one? Some dealers will exchange your monitor even if it only has one dead pixel, which is an ideal situation. There's a very real risk that your display won't be considered defective until it has eight dead pixels. That's eight too many. Faced with this prospect, the best thing to do is to start looking around for another dealer who offers you a better warranty.  A good reference is available at: http://www6.tomshardware.com/display/20030319/index.html

A Red Herring:

Don't let yourself be swayed by arguments about the monitor's vertical display capabilities. Pivot-enabled monitors allow you to display your pages vertically, but if you're using a 15" monitor, this function is limited, which is not to say useless. You can use the pivot function in the following situations:

  • Creating office documents. If you only work with text documents, displaying them vertically might be a real boon.
  • Editing images that are longer than they are wide. However, CRT monitors are better for this area anyway, since they display truer colors and have better contrast than TFTs.
  • Displaying Web pages. In an upright position, a 15" LCD has a horizontal resolution of 768 pixels. However, most Web pages are generally based on at least 800 pixels.

 

Click here to see a snapshot review of LCD monitors as collected April 2003

Last updated by: Manfred Grisebach, IST - Systems, June 14th, 2005