In the years since they have become the industry standard, many of us are still unsure what the difference is between an LED and an LCD screen. From our home TVs to the bright and bold digital retail and electronic window displays that we see every day on the high street, they have become a major part of our lives, but very few of us understand them on a fundamental level.
So, how exactly do these screens work and what actually is the difference between an LED screen and an LCD screen? The answers might not be as complicated as you’d think.
An LCD (liquid crystal display) screen is composed of the display itself and the backlight which illuminates it with a diffuser placed between them in order to keep the brightness levels consistent across the entire screen. The LCD itself doesn’t actually emit any light, and actually works by filtering the backlight into a number of individual pixels and colours.
The backlight controls the opacity of each pixel via electronic signals, so when the screen wants to show a black image it will attempt to block the light – while if it wants to show a white image, it will let more light through. For this reason, LCD screens are not able to display as complex and deep blacks as a plasma screen, but for larger applications (LCD menus and LCD billboards, for example) it’s often more than adequate.
One major benefit of LCD screens, particularly for commercial applications, is that they don’t use as much energy as their plasma counterparts. They also have the potential to be much brighter due to their backlight operation, which makes them suitable for well-lit rooms, and exterior daytime applications.
A drawback, however, is that the viewing angle is limited due to the depth of the screen. Granted, this is nowhere near as big a problem now as it was in the early days of LCD screens – given that screens are thinner, but it’s still limited compared to plasma.
There are two main types of LED display – backlit displays that use an array of LEDs to light the screen in a similar manner to an LCD display, and LED screens that work by emitting light in RGB colours directly from the face of the display.
Both options are more cost-effective from a manufacturing perspective, as LEDs (light-emitting diodes) are cheaper to produce than the CCFL (cold-cathode fluorescent lamp) tubes used in LCD displays.
The direct display option generally offers a deeper and more complex image. In principle (and in operation) LED screens are not significantly different from their LCD cousins. In fact, the picture quality between both is almost identical.
There are three main configurations of LED screens for domestic and commercial use:-
Direct Lit – This is the most affordable configuration and uses the least amount of LEDs. They are larger and can’t be controlled separately, which means they are able to provide less of a complex image. They are, however, perfect for larger, more affordable displays where higher definition is not that important. Note that these screens tend to be quite deep – given the space required behind the screen to fit the larger LEDs and diffusers.
Edge Lit – The most common form of LED screen. Indeed, it’s more than likely that the TV currently sitting in your living room uses this configuration. This places LEDs only at the edges of the screen, allowing the screens themselves to be that much thinner. As there are fewer LEDs than in a full array, you might have problems with dynamic lighting if your screen hasn’t been properly configured.
Full Array – Perhaps the most sought after type of LED backlighting (and also the most expensive), these methods distribute the LEDs evenly to produce a more consistent light, which allows for more dynamic colours and lighting. Some full array LED screens also use coloured LEDs, which allow for an even wider and deeper range of colours.
There was a time when buying a display meant evaluating if you could even afford the space or the money for one. However, things have changed since then as those bulky CRT displays gave way to LCD (Liquid Crystal Display) technology.
But even LCDs didn’t last long, as technology got better and better. LED screens took over the market, and the leading LED screen manufacturer brands have dominated ever since.
Many people looking to buy a display wonder what an LED display is and how it functions. So in this article, you will learn all about LED screens, display types, how they work, and why you should get an LED screen.
Looking to buy? Check out our guide to buying an LED Display.
LED stands for Light Emitting Diode. These diodes are tiny little bulbs that you might have seen on electronic devices.
Large LED displays use a large number of these diodes to light up the screen. These diodes are low power consumption devices that provide high brightness. As a result, an LED screen has several benefits over other display alternatives.
The fluorescent bulbs used earlier could only give black and white tones. However, an LED screen can display the entire colour spectrum by combining red, blue, and green colours (RGB).
The advantages of an LED screen are so many that you can find LED screens everywhere. From TVs to computer monitors to high-resolution billboards in shopping centres and LED video wall applications.
Even though LED display technology has become popular in the last 5-6 years, the evolution of the LED screen has taken over half a century. Here are some keystone events in this evolution:
Image: HP Model 5082-7000 Numeric Indicator
LED displays make use of a huge collection of light-emitting diodes on a flat panel. These diodes are either red, blue, or green. Each of these diodes is capable of emitting light of different brightness.
Just like you learned in art class, two or more colours can combine to create new colours. Similarly, red, blue, and green light from these diodes combined in varying ratios create every colour on the spectrum.
If you get close enough to an LED display, you can notice the individual diodes on the television panel.
While we are talking about LED technology, here are some technical terms that you should be familiar with:
Based on their construction, LED screens can be categorized into various types. Each of these types has its purpose. Here are a few of the common categories:
Dot-matrix LED displays are used to show numbers, alphabets, characters, and simple graphics. These displays consist of a rectangular array of LEDs followed by a space. They can be mounted serially to create a dot-matrix display.
These diodes are programmed to light up according to the number or character that is to be displayed. Each character requires about 5×8 pixels (or LEDs).
Because there is individual control over each LED, a dot matrix display provides more details and intricate graphics than a segmented display.
These displays can be used in meters, industrial controls, medical equipment, billboards, hoardings, and other uses.
7-segment displays are used to present numbers by splitting the display into 7 light segments.
These segments are arranged in a formation that looks like the number ‘8’. In this formation, every number from 0-9 can be presented by lighting the appropriate segment of the display.
These displays are one of the most common and simple and you will find them anywhere numbers are to be presented. A common example of this is digital clocks, digital thermometers, calculators, and other digital communications devices.
It is important to note that while 7-segment displays can recreate all the numbers, they cannot be used for lettering.
14-segment displays retain the basic 7-segment shape, plus additional LED segments placed in the diagonals and centre of the 8 shape.
These added sections make it possible to display letters along with numbers. This configuration is also known as the Starburst LED display.
These displays were popularized by arcade games in the ’80s. Even today, they are used in a wide range of applications that require specific requirements, such as a retro look or a simple alphanumeric display.
16-segment LED display improves upon the 14-segment design by further splitting the top and bottom horizontal segments of the 8-figure. The addition of these segments adds some clarity when displaying alphabets.
Segmented and dot-matrix designs are sufficient for basic graphics and alphanumeric characters. But they are unsuitable for purposes such as TV, computer monitors, or other displays that require recreation of a complete spectrum of colours and complex graphics.
For this purpose, the LED screens are large-scale in nature, employing millions of LEDs. Unlike the segmented displays, the complex large-scale arrangements do not have segments or gaps between the LEDs.
One important question to ask at this point is ‘why are LED displays so popular?’. If you remember the LED technology that we mentioned earlier, you might have guessed the benefits it can provide.
Even so, the advantages of LED displays are far more than what meets the eye at first glance. Some of them are:
Today, LED display solutions are used in a wide range of applications. Some of these include:
Even though LED screens have already replaced display technology everywhere, they still keep on evolving.
CRT displays remained in use for more than three decades. LED technology has been popular for only about six years, so it can be expected that it is going to remain for a long time.
One of the major driving factors for these displays is the various use cases outside of replacing television and indoor LED screens. Large LED displays such as LED video walls for advertising and digital signage in shopping centres are now common. These solutions make LED display technology much more diverse than any previously available solution.
While LED screens are already thinner than other alternatives, the size can be expected to be toned down even more. Another prediction is that the size of individual diodes decreases, thereby increasing the pixel density and significantly boosting the quality of an image on even the largest outdoor screen.
If you are thinking about buying an LED display for your personal or professional needs, don’t doubt your decision.
LED screens are the best technology available right now, whether you consider it as television on your living room wall or an advertisement window outside your office.