LCD TVs and LED TVs: Are they really different?

Nowadays, you can see a lot of people spending hours and hours together shopping for the perfect television which would occupy the center-stage of their respective living rooms. With the ubiquitous presence of ever-confusing marketers of the television-manufacturing companies, the decision is becoming all the more difficult. So, let us understand the technologies before you splurge your hard-earned money on them.

Earlier, you used to find televisions with only one kind of technology. They were called ‘CRT TVs’ (Cathode Ray Tube). With the help of electron guns, coils and a fluorescent screen, the CRT TV was able to produce a viewable image. Now, there were problems with this technology

1. A number of components were used to manufacture the television which made the processes of production, repair and maintenance difficult
2. The individual components were also bulky which made the television quite heavy  
3. Some of these televisions had a problem of ‘Image burn-in’ (Permanent discoloration of areas on electronic display) and a problem of ‘Image Loss’ at the boundaries of the display
4. These televisions produced noticeable flicker at low refresh rates
5. They consumed high power and generated a lot of heat

To overcome the drawbacks of this technology, manufacturers started producing LCD (Liquid Crystal Display) televisions. An LCD is a flat-panel display that makes use of light modulating properties of liquid crystals. Now, these liquid crystals do not emit light by themselves, so a backlighting source is required in cases where there is higher power consumption. To understand this, you need to take note that there are two kinds of LCDs: ‘Passive Matrix LCDs’ and ‘Active Matrix LCDs’. In ‘Passive Matrix LCDs’ like ‘Alarm Clocks’ and ‘Calculators’ where the power consumption is less, a backlighting source is usually not required. Contrast this with ‘Active Matrix LCDs’, where some sort of backlighting mechanism is required. Now, this backlighting has been traditionally achieved with a ‘Cold Cathode Fluorescent Lamp’ (CCFL) in an LCD Television. So, the ‘CCFL backlit LCD’ television overcomes the problems of CRT in the following fashion

1. They don’t use phosphor. So, the problem of ‘Image burn-in’ is eliminated
2. They can be configured to run at high refresh rates. So, the problem of flicker is eliminated
3. When compared to the CRT television, the components used are lighter in weight, so the heaviness of the television is reduced
4. They consume lesser power and generate lesser heat while lighting the entire screen uniformly
5. There is no ‘Image-Loss’ at the boundaries and the entire screen is viewable

Consequently, manufacturers found out that they could improve upon these televisions too by changing the backlighting mechanism. They found that they could bring about the following changes

1. Reduce the power consumption even further
2. Reduce the thickness of the display even further
3. Increase the image quality even further
4. Increase the brightness of the display even further
5. Reduce the weight of the display even further

The manufacturers used LEDs (Light Emitting Diodes) as a backlighting source instead of the conventional CCFL sources and were able to achieve all-the-above stated objectives. So, this gave birth to the ‘LED backlit LCD’ televisions. Currently, if you go shopping for an LCD television, you won’t find a true LED TV. The only things you will find are ‘LED backlit LCDs’. So, don’t expect to see a radically different picture altogether as compared to a ‘CCFL backlit LCD’, albeit the images produced by the ‘LED backlit LCD’ televisions are in fact much better. Even these televisions can be further classified into 4 different categories. I'll explain these categories in the next post

Stay Tuned..!!