When it comes to panel technology for a display bigger than side of a barn, liquid crystal and plasma technologies used in large screen TVs are out of questions. And those CRTs and organic electro-luminescence are not in count either. But the only existing technology that can be tapped in this case is light-emitting diodes (LEDs) viewable even in the sunlight. Reckoning what it takes to make Beijing Olympics opening ceremony eventful, the whole world applauded for 147 x 22 m LED screen installed on stadium floor.

Alongside dazzling presentation of the giant LED screen were mind-boggling multimedia lighting and video systems that made the display mesmerising. Thanks to the efforts of Yu Jianping, director of the technology group for the opening ceremony, overall technology and display at the event marked a new milestone in the world’s signage media industry.

Behind the screen

Believe it or not! Around 44,000 colourful LED beads were embedded with a distance of 600 mm between each to create myriad of the giant LED screen at Beijing Olympics opening ceremony. LEDs were fixed across an area measuring 20,000 sq m. And the foldable scroll made of aluminium alloy was placed on elevating platform on which thousands of artists performed. In order to create bizarre effects on the LED screen, 150 special projectors running on two projection systems were used

Tiny LED beads were also embedded on the costumes of performers who fanned out to create a falling starry sky and a brightly lit ‘Bird’s Nest’. The spectacular display collectively depicted five thousand years of Chinese history where different eras of its civilisation were flowed on a huge scroll of 200 mm thickness with magnificent digital direction and control system.

Whose technology is this?

Hong Kong-based Glux Gtek Inc. was the main architect behind the globally acclaimed LED screen at the opening ceremony. However, China must take hat off to Japanese electronics company Matsushita Electric Industrial Co for its remarkable contribution to the country’s signage industry. As long as the development of Chinese signage industry is concerned, the Japanese company introduced astrovision video screen to China.

Each astrovision screen consists of hundreds of LED units either in 7.5 x 7.5 inch or 14 x 14 inch arranged in a grid. Assembling of 1,296 LED units could create a display measuring 551 sq ft. And around 58,000 LED units can be installed per astrovison screen. Astrovision’s luminance is as high as 5,000 candela/sq m whereas the brightest PDP can offer only 1,600 candelas/ sq m.

United colours of LED

Each LED unit containing a layer of LEDs in a grid of red, blue and green diodes are placed at 8 mm intervals. When the screen is viewed from a distance of 10 ft, three primary-colour diodes blending together – appeared to be a full-colour pixel – produce realistic images in vivid hues. Each LED unit operating at 1.6 kHz offers fast response.

Advantage over plasma

In terms of brightness power, LED screen is technically superior to plasma screens. Technologically, self-emitting diodes used in LED screen generate high illuminative intensity. Apart from being able to increase brightness, far more than PDP, aestrovision panels are not flat as slanting sunlight deflected to the ground and away from the audience. This mechanism is absent in LCD or plasma flat panels.

LED units in astrovision screen serve as light source that can be seen from horizontal viewing angle as wide as 150o. Regardless of angles, LED screens always produce fine-textured images without any colour degradation. Rather than actions, spectators observing a 33 x 33 ft LED screen during the recent Beijing Olympics could see even athletes’ names and game results from a distance of 656 ft. However, LCD and PDP remain more effective for displays smaller than 23 sq ft.