Mar 10, 2017: A research team at the Hong Kong Polytechnic University (PolyU) claims it has successfully developed the most energy-efficient LED filament technology with a luminous efficacy of 129lm/W, which represents 1.5 times the efficacy of traditional LED lamps, surpassing all other general lighting tools available in the market.
A patent is now pending and the prototype design is completed. The team plans to conduct various tests and obtain certifications for market launch in 2017.
This LED filament technology has excellent energy efficiency. Based on the assumption of a daily operation of eight hours, a PolyU’s LED filament bulb with lumen of 1300lm costs HK$33 (USD 4.2) of electricity tariff per year, and contributes to 22kg of carbon dioxide emission per year.
In comparison, a traditional LED lamp costs HK$47 (USD 6) of electricity tariff and 31kg of carbon dioxide emission yearly with the same lumen and conditions, which means that the new technology can reduce carbon dioxide emission by 30%.
Besides, the new technology enables an expected lifetime of 50,000 hours, with only half of the production cost of traditional LED lamps.
The LED filament technology developed by PolyU also has other advantages including:
1. Wide beam angle: 300-degree, parallels to that of incandescent bulb;
2. Comparably high color rendering index (CRI): Enables original color projection of objects as if they are in natural light;
3. Less UV light emission; and
4. More environmental friendly: Absence of harmful chemicals, and consists of less electronic components, and 80% of recyclable materials.
These breakthroughs are made possible by the following technology advancement:
1. Using Aluminium as substrate material
Instead of ceramic and sapphires, Aluminium, with good thermal conductivity, high reflectivity and affordable price, is chosen as the substrate material, to achieve longer lifetime and higher lumen at a lower cost.
2. Mounting LED chips of small power on both sides of substrate
This design will reduce energy loss and generate even light diffusion, without affecting luminosity.
3. Applying PolyU’s advanced injection moulding technology
Applying advanced injection moulding technology developed by PolyU Advanced Optics Manufacturing Centre, a seamless and transparent spherical plastic case is produced to make 300-degree beam angle possible.
4. Enhancing power supply
PolyU LED filament lamp converts AC (alternate current) to low current DC (direct current) directly without dealing with the voltage, and hence reduces components required and simplifies circuits, enhancing reliability and efficiency of the lamp.