By Matthew Wade
A display device is responsible for converting the electrical signals it receives from a source into the static or moving content you see on screen. Curious about the various display technologies, standards and the accompanying terminology? Read on as Windows Middle East clears up the picture…
|~||~||~|At the heart of every display device sits an underlying technology, which is responsible for producing what you see on its screen. There are a number of these technologies in use today with the most common being CRT (Cathode Ray Tube), Plasma and LCD (Liquid Crystal Display).
CRT is the oldest form of display technology having been used for well over 100 years. Improvements have been made to the technology but even modern CRTs create their visuals using the same basic concept as their far older brethren. An electron gun fires a stream of electrons at a fluorescent screen, which when hit by electrons, emits light. An image is formed by manipulating the electron beam, using deflecting coils, in the shape of the visuals needed to be shown. CRT displays are on their way out, being replaced by newer LCD and Plasma displays.
TYPICAL LCD SPEC LIST: explained
2x HDMI ports
HDMI (High Definition Multimedia Interface) is a relatively new digital interface that is capable of carrying both audio and video data using just one cable. This means less cable clutter but more importantly, this interface also supports HDCP (High Definition Copy Protection). So, if you’ve got HDCP protected content and don’t have a HDCP ready interface such as HDMI or DVI with HDCP, you will not be able to play any HDCP protected audio or video content.
Full HD compliant
When a TV is 'Full HD' ready, rest assured it is capable of handling the 720p, 1080i and 1080p resolutions. If you find a TV that just says ‘HD ready’ it will only support the 720p and 1080i resolutions. Full HD TVs are slightly more expensive but will prove better buy in the long run.
1280 x 768 pixel native resolution
The native resolution of a flat screen, be it a LCD or a Plasma, is the resolution it will perform best at. While you can run at a lower resolution, most, if not all screens will produce a display with anomalies whilst sharpness will also be greatly reduced. The native resolution can also help you find out what modes of HD (High Definition) a TV supports. If a screen runs at 1920 x 1080 pixels natively for example, it can display 1080p HD content or if a display is capable of 1280 x 768, it can display 720p HD content.
1000:1 Contrast ratio
Contrast ratio is the difference between the whitest white colour and the darkest black colours a display can show. The greater this ratio, the more you’ll be able to see a difference between colour grades. So, a TV with a contrast ratio of 1000:1 will produce better shades than one with 800:1.
60,000 hours to half brightness
Hours to half brightness tells you exactly when your LCD or Plasma’s light source will reduce to half its original brightness. Every screen, regardless of whether it’s based on CRT, LCD or Plasma technology will, over time fade and will eventually fail altogether. When this happens you can either replace the light source or buy a new screen entirely.
Slim and trim
LCD and Plasma technology differ in terms of how they go about producing images and video on their screens although both also share a number of like traits. Both technologies for instance can be used to develop very large screens (as big as 103-inches for Plasmas) whilst the depth (from front to back) of the device remains fairly short. Using CRT technology to build a 103-inch screen on the other hand would require an immense depth (likely over several feet), simply because the electron gun would have to be very far from the screen, just so that the beam could reach all four edges of the screen.
Screens based on LCD or Plasma technology are also more economical in terms of power when compared to a CRT device of a similar size. Whereas a 21-inch LCD or Plasma screen would require well under 100 watts of power, a CRT would consume over 150 watts.
Between the two modern screen technologies however, LCD has a slight advantage over Plasma in terms of power draw, therefore if you want a light electricity bill opt for a LCD.
Another similarity between the two is that both have limited viewing angles. This means if you are looking at a screen which has a horizontal viewing angle of 160-degrees and you are sitting at 170-degrees to it (almost a right angle), brightness and contrast will fade and the picture will appear to turn black. Though Plasma screens once bested their LCD counterparts in this department, today’s LCDs outstrip Plasmas. It’s worth noting however that older CRT screens are completely free from these restrictive viewing angles.
In terms of colour representation, both technologies are capable of producing accurate colours with the exception of one; black. Today’s Plasmas are capable of producing decent blacks however, LCDs at best can produce a dark charcoal gray. (CRT displays are capable of producing the deepest, darkest blacks.) On the other hand, LCD screens produce colours that appear more vibrant so depending on your viewing preferences, you should pick your TV accordingly.
As LCD and Plasma screens are based on liquid crystal- and a form of gas-technology both aren’t as adept at producing very fast moving videos or images compared to light-based CRTs. It’s worth noting that the latest generation Plasma screens have almost closed the gap with CRTs. LCDs are still susceptible to displaying ‘ghost trails’ when extremely fast motion is depicted, even if the screen has a response time of between 10ms and 5ms Not quite perfect
The downside to LCD technology is that it is expensive and cannot produce very rich blacks. You might also find that LCD screens sometimes arrive with pixels that are stuck or ‘dead’ out of the box. Unfortunately most manufacturers will only replace the screen under warranty if between five and ten dead pixels are visible on screen. Plasmas suffer from ‘burn-in’ meaning that if you have a static object shown on screen constantly, the image will actually become permanent, even when you kill the power. Plasmas are also quite fragile which means the likely hood of receiving a damaged screen, due to the rigors of shipping, are more likely.
Boost your knowledge of the latest display products and technologies still further by checking out the Windows Middle East content listed here.
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