Plasma, LCD, DLP and CRT - Making Sense of TV Technology

Televisions and the technologies they draw on have advanced rapidly since Philo T. Farnsworth experimented with a stream of electrons in his Hollywood, California apartment. Farnsworth is the engineer most associated with the invention of the Television.

Today, TV technology has branched into different types. Each technology continues to progress quickly and has strengths and weaknesses associated with it.

Plasma

Plasma displays were developed in 1964; however, it wasn’t until the last decade that they were commonly used in televisions. Plasma TVs are flat panel, meaning they are very thin when compared to a typical CRT TV. Most plasma televisions are under 10 cm (4 in.) thick including electronics. They can easily be hung on a wall like a picture.

The technology behind a plasma, simply stated, involves two panes of glass that sandwich tiny cells filled with gas. The gas is electrically charged and ultimately excites phosphors to emit light.

Plasmas were the first flat panel TVs available to the public—Pioneer introducing the first in 1997. They’ve held a stronghold on the flat panal TV market; however, with recent advances in LCD technology, LCD TVs are quickly gaining ground.

Pros:

• No ghosting—plamas are able to display fast action, like in action films or sports, without ghosting.
• Plasma TVs are typically available in larger sizes up to 60 inches.
• Plasmas offer vivid, lifelike colors with deep blacks.

Cons:

• Plasma screens are subject to burn-in when a still image remains on the screen for an extended time. Nevertheless, newer models have technologies that help prevent burn-in.
• Plasma TVs use more power than their LCD counterparts.
• Plasma televisions are heavy and fragile making them more difficult to install and move.

LCD

Liquid crystal display (LCD) uses liquid crystals in each pixel on the screen to control the passage of light. Invented in 1971, LCD displays were first used in watches and calculators. However, the technology was quickly accepted and used in computer, medical and industrial electronics. In recent years, LCD displays have made a presence in the television market.

LCD TVs are flat panel, meaning they are thin and are easily hung on a wall or fit nicely in an entertainment center. Recent advances in LCD technology have made the LCD TV equal to and even better than plasmas in some aspects

Pros:

• Unlike plasma TVs, there is no risk of burn-in with an LCD television. This makes LCD TVs a popular choice for video gamers, sports fans and others who enjoy programs where there are stationary objects like a scoreboard.
• The first LCDs had a narrow viewing angle—meaning you had to sit directly in front of the screen to see the image clearly. Now most LCD TVs boast a wider viewing angle than plasma TVs.
• If you have a TV in a room with big windows or lights, consider an LCD. LCD screens do no have glare.

Cons:

• Older LCD TVs may have a ghosting effect when objects move quickly across the screen.
• On average, LCD TVs are more expensive than Plasma, DLP and CRT TVs.
• LCD screens typically have a lower contrast ratio causing black to be untrue.

DLP

Digital Light Processing (DLP) technology was developed by Texas Instruments in 1987, but wasn’t employed by TV manufactures until later. DLP imaging systems use either one or three electronic chips called Digital Macromirror Devices or DMDs. Each DMD is equipped with tiny micromirrors that tilt in response to an electrical signal. The tilt of the mirror directs light to create an image. Each mirror makes up a pixel.

DLP televisions are in between flat panel TVs and CRT TVs for thickness. Most DLP televisions are not thin enough to mount on a wall, but are much thinner and lighter than their CRT counterparts.

Pros:

• No possibility of burn-in—making DLPs good TVs for video games and sports.
• DLP televisions are more cost effective than plasma and LCD TVs.
• DLP televisions have a long life span; manufacturers list the backlight bulb life at about 80,000 hours.

Cons:

• Not as thin as LCD or plasma televisions, but newer models are thin enough to be wall-mounted.
• More mechanical than traditional CRT, plasma and LCD TVs.
• Some DLP sets with a single chip design can cause a so-called rainbow effect. This is the result of the use of an inferior color wheel.

CRT

Cathode ray tube, or CRT, televisions were invented at the end of the 18^th century. CRT was the first technology implemented in a television and is still used today. In fact, almost every household has a CRT television set.

However, as new technology develops, plasma, LCD and DLP televisions are replacing CRT sets. The biggest reason is because CRT TVs are big.

Pros:

• CRT is a very reliable technology and CRT televisions tend not to have many problems.
• CRTs are the most affordable televisions on the market today.
• Despite advances in other TV technologies. CRT television still offer comparable images with crisp, clear colors.

Cons:

• CRT televisions have a large footprint meaning they take up a lot of floor space. For example, a 34-inch CRT is 24 inches deep.
• CRT TVs are much heavier than plasma, LCD and DLP televisions. A 34-inch CRT TV weighs almost 200 pounds.