Explaining the Difference Between LED and LCD TVs

Difference Between LED and LCD TV

The difference between LED and LCD TV sets is something that many people misunderstand.

The acronym “LED” stands for Light Emitting Diode. A diode is an electronic component used to control the flow of current in an electrical circuit. An LED is a type of diode that when excited, or energized, emits light. The type of material used to construct an LED determines what color it emits when energized. One of the major reasons that LEDs are used so much is their low power consumption — typically three to five volts. Besides switching circuitry, LEDs normally don’t require any controller circuitry to operate because they are either on or off.

However, the acronym “LCD” stands for Liquid Crystal Display. An LCD is a type of display that delivers excellent clarity and crispness. The LCD device is connected to driver and controller circuitry that controls what is displayed. These devices are composed of a display background, usually with some sort of backlighting, covered by a piece of glass.

The Major Difference Between LED and LCD TV

Recognizing what is an LCD and what is an LED device is pretty easy: If the portable device has a button that has to be pressed in order to see it when the ambient light is low, chances are it’s an LCD device. On the other hand, if the device can be seen late at night when it’s so dark you can’t see a hand in front of your face without using a light source, you’re looking at an LED device.

“But Mike,” you say, “my TV is supposed to be an LCD TV and I don’t have to push a button to see it in the dark.” Patience grasshopper, I will get into that. First, let’s take a look at some everyday devices to see what technology they use.

Examples of Devices Using the Two Technologies

Both of these types of devices are becoming more and more ubiquitous these days. Many car makers are starting to use LEDs for lighting — headlights, taillights, interior lights — instead of incandescent bulbs, both because they are more efficient and because they give off more lights (in lumens or candlepower) than comparatively-sized incandescent bulbs. Other examples include the charging indicator on your cell phone, cordless razor, laptop, or phone is an example of an LED.

Except for TVs and computer monitors/displays, LCDs are actually becoming harder and harder to find these days. There are some notable exceptions. Do you own a digital watch? If so, that’s an example of a device that uses LCD technology. You’ve got to push the light button in order to see it, right? Most handheld calculators are also examples of devices that use LCD technology. The display on that old Sony/Memorex/etc. portable CD player you used to have is another example, as is the display on many older car stereos, with digital displays, as well as many of the newer fancier ones out today.

So … What’s the Difference Between LED and LCD TVs?

Basically, the difference is the fact that an LED TV doesn’t require an external light source, while an LCD TV does. You may remember from a few years back an advertising campaign for a new type of TV with the slogan, “It’s the mirrors” and wondered what mirrors have to do with your TV. The mirrors in LCD TVs are highly specialized, highly polished, and focused within minute tolerances to remove as much picture distortion as possible, as they reflect the light from the light source. Honest. That’s the main difference. If you check the manual for your LCD TV, you’ll find listed in the “customer replaceable parts” list that the only listing is usually for a small (and usually not cheap) light bulb. An LED TV has no user serviceable or replaceable parts at all.

The other difference between led and lcd tv is something I mentioned above as to why automotive designers and engineers are using LEDs more and more instead of incandescent bulbs-cost effectiveness. Because an LED doesn’t require an external light source, they’re cheaper to run; they require less voltage and current to excite and cause to emit light. Additionally, LEDs, because they have no glass, are more durable and less prone to damage from heat. They also tend to last longer for these same reasons.

Photo Credit: Philips_Ambilight_TVs