LCD Vs LED Vs Plasma: Picking the Right Tool for the Job
As with most things, picking the right kind of display for your needs is really a case of picking the right tool for the job. LCD, LED and plasma displays all have their good and bad points.
LCD or liquid crystal displays are based on passing a current through crystals to allow light through in some areas and not in others. This happens by using two polarised filters at right angles to each other. This typically blocks all light; however, by twisting the crystals the polarisation of the light is changed and thus allowed through. This is why if you’ve ever looked at a computer screen through a polarised lens (often found in sunglasses or modern 3d glasses from a cinema) you will find that at certain orientations you can see the screen clearly, however at others you won’t be able to see anything.
LED TVs are actually just another type of LCD; the main difference is the backlight source. Typically in LCDs, especially older ones, the backlighting comes from cold cathode tubes, which fully cover the rear of the screen at all times. In LED LCDs, an array of LEDs provides the backlighting and can be individually brightened and dimmed, allowing bright objects to be brighter and dark objects to be darker. For example, when looking at a very bright object such as the sun with a silhouetted rock in the foreground, an LED array can react to increase the backlighting on the bright object and reduce the backlighting on dark areas of the screen making the contrast a lot stronger. Also, since the backlight is based on LED technology and not all of the LEDs have to be active at the same time it makes LED TVs a lot more energy efficient as well.
Plasma screens typically offer the best visuals. These feature a large number of small plasma cells which emit light when light is passed through them. The result is very clear colour definition and high contrast. However, plasma screens are not particularly energy efficient and can suffer from burn-in, where if an image is left on them for a long period of time that image can leave a permanent mark on the screen even when viewing other images; a big problem for a lot of channels which have their logo in one corner of the screen.
For home use, all three have their place and all are popular, though perhaps not equally so. LED LCDs are generally considered the top dog by today’s standards, as they offer some of the best pictures and are highly energy efficient, though they are a lot more expensive than their plasma and normal LCD counterparts. Plasma screens do offer a cheaper way to get a good picture, but do come with a few drawbacks such as the increased power usage and the risk of damage. Standard LCDs offer a very good budget solution; being generally the most inexpensive, the picture quality won’t be quite to the same standard as plasma or LED TVs, however they are still relatively low on power consumption and you won’t run the risk of damaging them if you leave a film paused.
For public displays LCD and LED screens are generally a better choice. There are a number of reasons for this and it depends on what you’re using your display to advertise, but in general, public displays are likely to be left on for long periods of time and may be left on a single image for large proportions of that time, which would be damaging to plasma technology. You also have the power consumption to consider. Both LED and LCD displays will use significantly less power, which can make a big difference when you have a large number of screens running potentially 24 hours a day.
The difference between picking LED LCD or standard LCD really comes down to how crisp you want your image to look. For advertising high definition video, the obvious choice is going to be LED LCD, with its eye-catching high contrast and vivid colour. For most other applications, though, the cheaper LCD variations will perform just as well.
In a similar vein to advertising displays, industrial displays are also likely to display the same image for long periods of time, making LCD displays better suited to their needs. Power consumption is of key importance here too, since screens will often be running 24 hours a day. While it can be important to keep the cost down, it’s not unheard of for LED screens to feature super-bright backlights. These are used to make screens readable in high light conditions where screens may be situated in strong sunlight.
For overall effectiveness and versatility, the standard LCD offers the best solution for the price, being by far the most versatile and cost-effective solution. LED TVs, on the other hand, have really cornered high quality visuals leaving plasma displays slowly dwindling as a technology.