HDTVs have finally become an accepted standard in most homes. In the world of HDTV, the older technology of a plasma television has been largely supplanted by the LCD TV. LCD TVs have made up the bulk of televisions bought and sold for a few years now. However, Cable TV Advisor has an overview of a new development that’s on the horizon, offering consumers a higher-quality, longer-lasting option: the LED TV.
How LCD TVs Work
LCD (liquid crystal display) TV screens are made up of a matrix of twisted crystals. When powered up, individual cells in this grid of crystals open up to selectively filter white light from the primary light source behind the screen, the Cold Cathode Fluorescent Lamps (CCFLs). Different colors are generated based upon how much the crystals open. These CCFL tubes are always on when the LCD TV is operating. There are a couple of problems with this internal architecture. Firstly, because the CCFL tubes are always on when the TV is powered up, true black can’t be produced. When black needs to be produced, LCDs close individual crystals in front of the CCFL tubes. As a result, there are always varying degrees of light bleeding through, which adds a grayish tint to things that are supposed to be black. This also leads to a lessening of color contrast. Secondly, LCDs have a shorter lifespan. The primary light source on a LCD TV is always on when the TV is powered up. Eventually, the luminosity of these tubes lessen with use, eventually dimming considerably.
Benefits of a LED TV
Compare the above architecture to an LED TV. The thing that is unique about LED TVs is their light source. Instead of using standard CCFLs as a light source, they use a collection of light-emitting diodes to generate luminosity. This manufacturing difference offers several benefits. The standard row of CCFL tubes behind a LCDTV are replaced with panels holding up to a thousand individual LEDs. These diodes can be turned on, off or even dimmed in groups, in a process known as localized dimming. As a result, LEDs offer some unique benefits.
Instead of creating blacks by closing off areas of a liquid crystal matrix, the diodes in a LED can be turned off individually. This technique offers truer, deeper blacks with little to no bleed, which in turn improves contrast. Not surprisingly, LED TVs also emit white light in a broader spectrum than LCDs. In addition, the LEDs, by design, have a much broaded color spectrum. In the age of digital content this leads to a much richer viewing experience. LED TVs are also more energy efficient. It takes roughly 40% less energy to power these televisions when compared to a LCD TV, primarily due to the flexibility of the internal architecture. Also as a result of their unique structure, LED TVs have a much longer life than an LCD TV. The diodes in the LED do not dim over time the way the tubes in LCD does.
LED TV Options
Consumers have more than one type of LED TV to choose from. The primary type, described in this article, is the back-lit LED. The other option available is the edge-lit LED TV. Edge-lit TVs feature a ring of LEDs around the edge of the television, outside of the crystal matrix. Through a process of diffusion, this light is then dispersed across the television’s surface. Because there is no panel of diodes behind the screen, edge-lit LEDs can be very thin. However, because there isn’t direct power behind the screen, the picture and color quality is significantly lower than with back-lit LEDs.
LED TVs are the latest iteration of HDTV technology. By offering a higher quality picture, better contrasts, and a longer lasting light source, they are clearly a strong option for consumers looking to make a foray into the world of HDTVs.
Eric Halberg has been installing cable in homes for over a decade. He enjoys sharing his tips and stories on various home entertainment blogs.