“The LED Television Set”

As I write this, the countdown has began for the introduction of Digital Television Broadcasts. A number of countries have already or are in process of switching over their signal from the current analog to the modern digital signal. Many TV manufacturers have already embarked on the manufacture of the modern sets. A lot has been said about the “LED” Televisions; even many sales professionals that ought to have known better what it is all about are simply misrepresenting what a LED Television is to their potential customers. First and foremost, let us recall what a “LED” is; it is a Light Emitting Diode, the word behind the term LED. To set the record straight, it is important to note that the LED designation refers to the backlight system used in some Televisions, not the chips that produce the image content. In the CRT (Cathode Ray Tube) TVs, the CRT produces the light, but when it comes to the newer versions like the LCD (liquid Crystal Display) and its next of kin, the LED, these use a form of thin screen that displays the image, but for this to work well, there is a need for a backlight that illuminates the display to make the image on the screen to be visible. This is like holding a touch behind a newspaper so that, one reads it more clearly. In this case, the touch becomes part and parcel of the newspaper instead of being an external lighting. LCD chips and pixels do not produce their own light. In order for an LCD television to produce a visible image the LCD’s pixels have to be “backlit”. LED TVs are still LCD TVs. It is just that these new sets use LED backlights rather than the fluorescent-type backlights used in most other LCD TVs. There are currently two main ways that LED backlighting is applied in LCD flat panel televisions. One type of LED backlighting is referred to as Edge Lighting. In this method, a series LED backlights are placed along the outside edges of the screen. The light is then dispersed across the screen. The advantage of this method is that the LED/LCD TV can be made very thin. On the other hand, the disadvantage of Edge lighting is that black levels are not as deep and the edge area of the screen has a tendency to be brighter than the centre area of the screen. The other type of LED backlighting is referred to as Full-Array (also referred to sometimes as Full LED). In this method, several rows of LEDs are placed behind the entire surface of the screen. The advantage is that these sets can employ “local dimming”. Local dimming means that each LED or a specific group of LEDs can be turned on and off independently within certain areas of the screen, thus providing more control of the brightness and darkness for each of those areas, depending on the source material being displayed. On the other hand, LCD TVs that employ full array backlighting are thicker than LCD TVs that employ an Edge-lit LED light source. (to be Cont’d) eddie@afrowebs.com