LED, LCD and OLED TVs and Displays
Modern ‘flat screen’ televisions are now some combination of the above. Despite having a different acronym, an LED TV is just a specific type of LCD TV. The proper name would actually be “LED-backlit LCD TV,” but that’s too much of a mouthful for everyday conversation, so people generally just refer to them as LED TVs.
An LED TV uses a liquid crystal display (LCD) panel to control where light is displayed on your screen. These panels are typically composed of two sheets of polarizing material with a liquid crystal solution between them. When an electric current passes through the liquid, it causes the crystals to align so that light can (or can’t) pass through. Think of each crystal as a shutter, either allowing light to pass through or blocking it out.
Around a decade ago, it was possible to buy LCD screens that were backlit by other means, however these are now rare as they are less efficient, offer less contrast, and are bulkier.
OLED screens are much the same, but use ‘organic’ LEDs for backlighting, which can be much thinner as they respond to current being passed through them in a thin sheet rather than as a series of individual pixels soldered onto a large board. OLED baclighting is currently more common in consumer screens than commercial as they can be fragile and the technology is less proven.
Plasma TVs are the original ‘flat screen’ display that you may still have in your home. They were incredibly popular in the late 90’s and early 2000’s as the standard screen in homes and commercial use, however were surpassed by LCD screens once LED backlighting became accessible in the 2010’s. Some people still believe they offer a more ‘natural’ picture, however the drawbacks are numerous, such as weight, size, fragility, and the potential for ‘screen burn’ where a very bright image can leave a ‘ghost’ of itself if displayed on the screen for too long.
Confusingly, another completely different type of display is also often referred to as ‘LED screen’. These are large-format LED walls which are used at events where a sharp, bright image is required to be displayed on a greater scale. Where LED-backlit LCD screens are commonly only available up to 2m across, LED walls are only really useful at sizes larger than this.
An LED wall usually is comprised of seamless square or rectangular panels of between 0.5m and 1m wide. The panels lock together to form a larger screen and can be hung from the ceiling or mounted on the floor depending on the venue. The dots or ‘pixels’ that make up the image are much further apart than with a standard TV screen. LED wall panels are often defined by this distance between pixels; for example a ‘P3’ LED wall will have pixels that are 3mm apart. For reference, a 40” consumer TV will have pixels that are around 0.5mm apart. This is sometimes referred to as the ‘pixel density’. The lower the number, the higher the pixel density.
LED walls have been available for decades, however until recently were only recently useful for festivals and large events where P12 or even lower density screens were appropriate. In recent years the lower cost of components and greater technologies available have meant that LED walls of P3 or even higher density have become available for many more applications such as exhibitions, awards shows, and conferences.
The positives of LED wall are numerous, they are incredibly bright, can be built to many sizes and shapes, and some can even be curved. However it does have some drawbacks; it can be expensive, it requires very skilled technicians to set up and operate, and it requires certain rigging to erect safely which some venues may not have access to.
Often the staple of smaller events, many people will already be familiar with projection. It works by shining a bright image onto a surface, either from in front or behind. The benefits of projection are that it is relatively inexpensive on a small scale, and can be achieved with relatively little equipment. It does have numerous drawbacks however, such as poor visibility in well-lit conditions, and the requirement for a projector to have uninterrupted line of sight between itself and the surface.
CRT or Cathode Ray Tube screens are the old television sets that were common until the 21st century. They are often remembered as heavy glass screens encased in large boxes. They have largely been surpassed in quality and affordability by the types of screen referred to above, however a small selection of enthusiasts and graphic designers still prefer CRT due to its richer colour rendition and higher contrast in the very high-end units.
They are also great as an ‘old-school’ prop!
For more advice on screen types and what is right for your event, get in touch!