CRT TVs: The Cathode Ray Tube Still Reins
The good old fashioned picture tube is still king!
The CRT is the Cathode Ray Tube, or picture tube, the most common kind of TV available. We've all seen the heavy glass tubes that have dominated most middle-American living rooms for generations. The science behind these displays is long lived, well proven and very reliable. The direct-view CRT still provides the reference quality video largely used by the entertainment industry to gauge their products from video players to new DVD movies. The display quality of a direct-view CRT capable of HD resolutions is easily among the best available and at a price point that no other display type can touch. Many will say the CRT is reaching the end of its life cycle, that it's being replaced by other, better display types. But for the cost and the gorgeous results of a CRT picture it's sure to be around for some time. Until they start making LCD panels with zero dead pixels and for about the cost of a CRT, the humble picture tube is in for a long stay on the shelves of electronics stores.
The CRT works by firing electrons from the back of the tube into its face. This cathode/anode electronic reaction creates an electron sweep of light and images across the face of the tube. This is why CRT is unique among display technologies - it's not a fixed-pixel design, in fact CRT is the only one of the modern display technologies that aren't considered fixed pixel. The CRT's resolution is not measured in pixels; instead CRT's image detail is measured in scan lines. 480 scan lines have been the standard of visible scan lines on TVs since the NTSC first logged this as the video standard that was adopted for much of the world.
CRT pluses- Low cost.
- Over 50 years of engineering has produced a technology at the top of its game.
- 1080i is a higher "on paper" resolution than 720P.
- Image quality is on par with anything produced today.
- Biggest and heaviest of all display types.
- Direct view tubes are limited to about 40".
- Use the most energy of all displays.
- Burn-in is a factor.
The most obvious benefit to choosing a CRT-based display is the price. You can't beat the low cost of picture tube TVs with any other display type. High-definition TVs that use CRT will have a native resolution of 1080i - higher than 720P, which is the native resolution for any of the fixed-pixel display types. However, this "advantage" is only a number on paper. The same amount of digital bandwidth is used for both, since basically they display the amount of information at the same time. So really, the number 1080i is just a bragging right until your friend gets a fixed pixel display that is 1080P - then fixed pixel will clearly have more lines of resolution than CRT.
The biggest technical problem that has existed for CRT is burn-in. Burn-in is where a static image is left on the screen for extended periods and literally burns the phosphor material on the inside of the face of the tube, leaving a visible ghost of the image that was burned in. The most explicit examples are early computerized cash registers or computer monitors that were used for a single purpose, such as an ATM. On older ones suffering burn-in you can see a ghost of the logo or whatever the image was that was left on the screen for long durations. The reason screensavers are popular with computers these days is to help your computer monitor avoid burn-in. Although burn-in is a serious problem for CRT, it is not unique to CRT only. Plasma can also suffer burn-in - an extreme problem for the most expensive TVs that suffer the same malady as the humble picture tube.
