University spin-off unveils 129lm/W LED filament lamps

March 14, 2017 // By Julien Happich
A research team of State Key Laboratory of Ultra-precision Machining Technology (Partner Laboratory in The Hong Kong Polytechnic University) and PolyU students have developed what they believe is the most energy-efficient LED filament technology, with a luminous efficacy of 129lm/W, approximately 1.5 times the efficacy of traditional LED lamps.

In 2015, PolyU Micro Fund had awarded a seed fund of HK$100,000 to the student team, last year, the seed fund was increased to HK$120,000 (approximately 14,530 euros) and the students are hoping to launch their product this year.

According to their calculations, the LED filament technology they developed could reduce carbon dioxide emission by 30% compared to traditional LED lamps while being 50% cheaper to produce and boasting an estimated lifetime of 50,000 hours. Another key benefit of LED filament technology is the wide beam angle (300º), close to that of traditional incandescent bulbs.

In their development, the researchers used thin beams of aluminium as the substrate material instead of ceramic and sapphires, combining good thermal conductivity, high reflectivity and an affordable. They mounted many tiny low-power LED chips on both sides of the substrate, reducing overall energy losses compared to the use of higher-power LED chips while ensuring a more even light diffusion (for equivalent luminosity). Beam angle was optimized through the design of a seamless and transparent spherical plastic case formed via proprietary injection moulding technology developed by the PolyU Advanced Optics Manufacturing Centre. In order to improve the power supply efficiency and design simplicity, the PolyU LED filament lamp directly converts AC (alternate current) to low current DC (direct current) without dealing altering the voltage, and hence reduces the number of components required and simplifies the circuit design for improved reliability and efficiency. Patent have been filed for the technology and the team is busy conducting various tests for market qualification and launch.

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