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Huge Times Square Sign Uses LED Technology
Lower cost of LEDs enables designers to increase the number of LEDs by 25-fold
Charles J. Murray, Senior Technical Editor -- Design News, June 1, 2008
Using more than two million bright, low-cost, light-emitting diodes (LEDs), engineers have created a 3,200-sq-ft “super sign” capable of displaying full-motion, high-definition (HD) video.
Located in the Times Square area of New York City, the sign provides a dramatic improvement in resolution over its predecessor, largely because LEDs have dropped steeply in price over the past seven years.
“The reduction in cost of LEDs has allowed us to push the envelope and improve the resolution,” says Meric Adriansen, founding partner of D3 LED, the digital display company that designed the sign for the American Broadcasting Company (ABC).
D3 LED pushed the envelope by decreasing the dot pitch between the LEDs. Instead of the 50-mm pitch used on a 1999 version of the sign, the company’s engineers used a 10-mm pitch. In essence, that meant the new sign had a 25-fold increase in LEDs ( five times as many devices in the vertical and horizontal directions). Adriansen says such an increase was possible because LEDs now cost about one-third as much as they did in 1999.
In the design of the sign, engineers employed 3- x 40-inch electronic modules containing 800 Super Oval LEDs from Nichia Corp., along with embedded processors, control systems, cooling fans, logic and a Gigabit Ethernet data bus to enable the sign to “talk” to its data source. In all, the company used 3,550 such modules, carefully spaced along the curved, 935-ft-long “ribbons” of signage.
“Basically, you have 3,550 computers linked together on a Gigabit data pipe, communicating thousands of times per second, getting pieces of the imagery and displaying it,” Adriansen says.
Despite the huge increase in LEDs over the original 1999 design, engineers also faced the task of maintaining power consumption at 1999 levels.
“Even though we were increasing the resolution, it didn’t mean we had the luxury of drawing much more power,” Adriansen says. “We had to stay within the same power footprint as before.”
At full brightness, the new sign draws 600A of three-phase AC current at 208V. Total power draw is about 215 kW.
Adriansen says ABC’s choice of an LED-based sign was necessary to meet its needs. Plasma screens, he says, are far too small and projection screens couldn’t have operated in daylight, as the Times Square sign is expected to do. “In order to create big signs that can penetrate through the brightness of daylight, you need LEDs,” he says.
The resulting 3,200-square-ft sign is said to be the only one in the world that has nine horizontally-arranged, three-dimensional curving, undulating parts.
“At the time the sign was first built in 1999, it was considered revolutionary,” Adriansen says. “Our customer wanted it to be revolutionary again.”
