“I thought it would be clumsier,” said Nick Holonyak Jr, the engineer behind the first visible light emitting diode (LED), in a 2012 corporate video 50 years after he invented it for General Electric. “And you know what, this isn’t the end.” Engineers at Polytechnic University seem to have shown this is true by developing a new LED filament bulb, which they claim is the most energy efficient of its kind on the market. “It can replace the traditional LED bulb,” said inventor Ricky Chiu Chung-chi, 25, who graduated from the industrial and systems engineering department last year. Costing just half the amount to produce than a normal LED, HK$20 against HK$44, Chiu said his bulb packed up to 129 lumens per watt, 1.5 times the efficiency of a regular LED bulb. When it comes to electricity bills, that’s about HK$33 in savings a year based on eight-hour daily use. It also means 30 per cent fewer carbon emissions than a normal LED over a one-year period. Furthermore, with a 50,000-hour lifespan, bulbs do not have to be changed so often compared to traditional LED bulbs that may last between 15,000 and 30,000 hours. About 80 per cent of materials are recyclable. “I always wondered why LEDs and regular fluorescent bulbs had such wide differentials in cost, efficiency and illumination. So I set out to develop something which would combine strengths in these three areas,” Chiu said. The use of aluminium in the substrate of the filament minimises heat damage on structure and luminosity, allowing for a longer lifespan and higher efficiency, Chiu said. Tiny LED chips on both sides of the substrate minimise energy loss and generate even light diffusion. The ability to convert alternate current to direct power also rules out the need for a transformer, allowing bulbs to be plugged into all light fixtures, said Dr Sandy To, associate head of the State Key Laboratory of Ultra-precision Machining Technology, one of PolyU’s partner labs, who is advising Chiu’s team. The invention was the basis of Chiu’s final undergraduate project, but it eventually caught the eye of his supervisors. He won HK$100,000 in seed funding from the PolyU Micro Fund in 2015 and another HK$200,000 from To’s lab. A patent is now pending. Several manufacturers are said to be interested. Chiu believes the product will hit the market later this year and will cost about HK$45 in the shops – about half that of a regular LED bulb.