Take a peek at the tech behind a giant outdoor LED display

Find out more about these often seen but mostly ignored outdoor advertising LED screens and the technology behind them.

Aloysius Low Senior Editor
Aloysius Low is a Senior Editor at CNET covering mobile and Asia. Based in Singapore, he loves playing Dota 2 when he can spare the time and is also the owner-minion of two adorable cats.
Aloysius Low
4 min read

These huge outdoor LED displays are a feature of everyday life in big cities. But what's behind them? Aloysius Low/CNET

SINGAPORE -- With an enviable grace that came from years of practice, Shaw Organisation Vice President Terence Heng scrambled over the narrow ledge, peering down at the scaffolding that would soon cover his company's entire outdoor LED display, located in the bustling shopping street of Orchard Road here in Singapore.

Meanwhile I stood cautiously at the edge, looking at the four-storey drop and wondered if my work insurance covered this. It probably did, but I wasn't in any rush to put it to the test. For Heng, the scaffolding meant renewal -- this 14-year-old screen would be taken down and replaced with a newer version that would be able to display sharper-looking commercials and cinema trailers.

In my case, well, I was here to take a peek at something most of us barely give a passing glance.

A look behind a giant LED display (pictures)

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As I carefully made my way up the semi-hidden stairway to the dark entrance behind the vast LED screen, I paused at the sight of the narrow dust-filled room. Heng walked in indifferently, pausing to turn on the light and gave me a hand up a small ladder as I scrambled to get inside.

"I've been in worse conditions, like when it was raining and the screen malfunctioned," said Heng, when I asked him about his nonchalance. "With the first board we had in 1999, to reset the screen, one had to get behind the screen structure, turn off the controllers, head back to office, restart the players then back behind the screen again to power everything up."

Heng added that the new system would actually solve this issue, since the server would then be located in his office on the 15th floor, instead of in this small alcove behind the LED display.

This display has been around since 1999, and was due for an upgrade. As you can see, it's much smaller compared with the newer screen at the top of this story. Shaw Organisation

Outdoor LED displays are something most of us have seen and ignored. Used mainly for advertising, these screens adorn the walls of shopping malls, city plazas, even at last year's Sochi Winter Olympics. Shaw's upgraded display will be using the same model as the ones in Russia, and will be one of the first few locations in Asia to deploy the new screen.

Unlike the more conventional LCD-based screens used in televisions, these panels consist of thousands of LED lights, each individual dot projecting a specific color matched to a frame to render an image. It's the same process that takes place on your typical glass screen found on a smartphone, but on a much larger scale.

These are what LED panels look like when you're really close. Aloysius Low/CNET

Of course, these displays are designed to be viewed from further away, since up close, you see nothing but colored dots. And depending on the size of your screen, the distance between each pixel also plays a part in how sharp the end result appears.

For Shaw Theatres, a movie chain owned by Shaw Organisation here in the island nation, upgrading the screen meant going from one 11 meters (36 feet) wide to 16.6 meters (54.5 feet). The wider screen would also be better quality, with a pixel density of 10mm compared with the 24mm of the older, and capable of playing HD content. Think of it as going from a 480p display to a top-of-the-line 1080p screen. Shaw declined to share how much the upgrade cost.

"The extra pixels allow us to put in better quality content -- movie trailers come in HD mostly -- instead of down-converting them. And use the screen real estate for more creative content," said Heng.

When I returned a few weeks later to check out the new screen, the dangerous-looking ledge was gone. Instead, the wider screen took up most of the real estate, making it a much safer climb into the alcove. Gone too, was the dust, though that's likely set to return in a few months, given the proximity of the screen to the nearby road.

Panasonic, which supplies the new LNPP10 panel, told me more about the new tech. Where the old design required a ladder for access to replace faulty LED panels, the new modular ones come with built-in climbing bars. You could easily climb all the way to the topmost panel without a ladder, as Heng was quick to demo to me.

Shaw Organisation Vice President Terence Heng climbing up to show how easy it is to access the panels for maintenance. Aloysius Low/CNET

The new panels are also easy to replace, with the locking mechanism letting maintenance crews quickly take out and put in a new one without too much fuss. Compared with the bulky older design, the newer panels are also much lighter and utilize a three-in-one configuration -- that is, blue, red and green diodes set close together to act as one main pixel.

Panasonic has also added small covers located above each LED that help increase visibility and contrast even under bright sunlight. But the best feature is the built-in redundancy data protection. Data flows two ways, so in the event of a faulty sub-processor, the other route kicks in. So you really only need to replace a panel if both sub-processors fail, which you can do easily by pulling it out and plugging a new one in its place.

From what I could see from across the road and below the display, the newer screen was much sharper, and even in the bright outdoors, I could appreciate much better contrast in the new "Hobbit" trailer.

The next time you walk past a giant outdoor LED display such as the ones in New York's Times Square or London's Piccadilly Circus, be sure to take a second or two to marvel at just how far technology has progressed and appreciate the really expensive ad you're seeing.