The bottom line with LCD monitors is that few of us can afford anything larger than a 15-inch model, which at this writing typically costs between AU$600 and AU$1,000. Opt for a 17-inch model, and the price doubles, while an 18-incher easily triples the price. Cost of manufacture remains fairly high across the board, but, according to Stanford Resources, because of excess inventory, many manufacturers are actually selling 15-inch LCDs at a loss.
| Terms you should know |
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LCD: a liquid-crystal display is created by sandwiching an electrically reactive substance between two electrodes. LCDs can be darkened or lightened by applying and removing current. Large numbers of LCDs grouped closely together can act as pixels in a flat-panel display. TFT: the prevalent technology for building the LCD screens for both desktop displays and laptops. TFT screens are brighter and more readable than dual-scan LCD screens but consume more power and are generally more expensive. Native resolution: the setting for LCD monitors that produces the sharpest picture. Unlike CRTs, LCDs work best at one resolution because there are a set number of pixels on the screen. Nits: short for candelas per square meter, a unit of measure for brightness Stuck/dead pixel: a pixel on an LCD screen that is either permanently on (stuck) or permanently off (dead) |
Compare these prices to CRT prices, and you'll see why so many desks still are giving up lots of real estate to clunky CRTs. Remember, however, that LCD dimensions measure the viewable area (diagonally), while CRT dimensions include the bezel.
All is not always what it seems in LCD land. For example, you'll see LCDs driven by a digital signal advertised as superior to those fuelled by an analog signal. But the gap has closed dramatically, to the point where you have to look very closely to tell the difference. To run a panel in digital mode, you need a special graphics card with a digital video interface (DVI) port and a special cable, so most people don't bother. According to Stanford Resources, about 64 percent of LCD monitors accept analog input only, 29 percent support analog and digital, and 7 percent take digital only.
Expect more variation in price and image quality among LCDs than among CRTs; LCD technology is newer than the trusty cathode-ray tube and is still evolving. You're even more strongly advised to have a look before you buy. Again, the specs tell you only so much. If you choose an LCD that claims high-end numbers for all of the following parameters, you'll very likely get a better view, but you'll probably pay a lot more.
Resolution. Due to superior LCD sharpness, smaller screens look better at higher resolutions than CRTs can comfortably display. In the LCD world, the optimum resolution is termed the native resolution, which correctly implies that any other resolution may not be a smart idea. Here are the native resolutions for the three most common LCD monitor sizes:
Why do 17- and 18-inch monitors share the same native resolution? Mainly because some people find text at 1,280x1,024 a little small on a 17-inch LCD--and 18 inches isn't large enough for 1,600x1,200 resolution. Because you can't count on a crisp image at any resolution besides the native one, make sure a panel's native resolution pleases you. In inexpensive, 15-inch models, the scaler chip, which maps the screen to alternate resolutions, may be particularly weak and yield blurry images at anything but native resolution.
Luminance. The luminance (or brightness) of LCD panels is measured in candelas per square meter (cd/m2, otherwise charmingly known as nits). This is not an easy number to find, but it's worth digging up on a manufacturer's Web site since more nits generally mean a more pleasing image, particularly in harsh lighting conditions. The range stretches from around 170 nits for a cheap panel to around 300 nits for the best--equal to a bright CRT.
Pixel response rate. This is another buried yet telling spec. It refers to the amount of time it takes for a pixel to turn on or off. If you're serious about watching or editing movies on your LCD, you might even want to call the manufacturer and get the number, or numbers, since the manufacturer may give you a rise time and a fall time. Movie mavens should look for a rise time of 10-20ms, while the fall time should be no more than 35-40ms.
Contrast ratio. If manufacturers used consistent methods to measure this spec, it might be a good indicator of image quality. Manufacturer-claimed contrast ratios, which describe the difference between the darkest and the lightest areas of a test screen, range from 200:1 to 500:1. But when you add a little ambient light to the equation, contrast decays dramatically. Better screen coatings can help stave off this decline, however, which is the main reason this spec is largely irrelevant.
Viewing angle. This is actually two numbers: the horizontal viewing angle and the vertical viewing angle. You don't need to worry much about this spec unless you plan to use your LCD for desktop presentations, in which case, you should insist on viewing angles of at least 120 degrees horizontal and 100 degrees vertical. About the widest you'll find on an LCD is 160 degrees for both horizontal and vertical viewing angles--a number many LCDs claim these days.
Warranty. Two points: First, as soon as you take your LCD monitor out of the box, load a blank white page and check the screen carefully for stuck pixels (tiny spots that stay black, white, or some fixed colour no matter how the image changes). Try the test again with a black screen and look for pixels that stay lit, although dead or black pixels are the most frequent problem. You can probably live with one or two stuck pixels, but a cluster of them is unacceptable. Second, although the usual LCD monitor warranty lasts three years, make sure that it also covers the backlight, because backlights have a relatively high failure rate.
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