Light utilization rate reaches 92% — New LED lampshade reduces light pollution

　　Ordinary LED lampshades have a light utilization rate of only about 70%, but a professor at National Central University in Taipei has developed a new LED lampshade with a light utilization rate of up to 92%, which not only saves energy but also reduces light pollution.

　　Professor Sun Qing-cheng of the Department of Photonics at National Central University: 'A regular diffuser spreads a beam of light into a long, strip-shaped direction.' To reduce light pollution and achieve better light utilization, Professor Sun created a globally unique design. The lampshade of an ordinary LED lamp uses a volumetric scattering diffuser. When light shines from above downward, about 70% of the light goes downward, but approximately 30% scatters toward the sky, causing light pollution, while the brightness on the ground is insufficient.

　　In addition to evenly distributing light by controlling its refractive index and angle, the micro-structure diffuser achieves a light utilization rate of over 92%. For example, the lighting fixtures in the National Central University badminton gym have been designed so that light falls only on the court and does not shine toward the ceiling. Professor Sun Qing-cheng of the Department of Photonics at National Central University: 'It is about light shaping — that is, allowing light to shine in the direction I want it to, with full control.'

Lighting has greatly influenced human development, but it also brings serious light pollution problems. In cities, it is almost impossible to see a sky full of stars. Sun Qingcheng, a professor in the Department of Optoelectronics at National Central University: "The light source of traditional lamps is simply too large, so ordinary lampshades cannot shield the light source well, leaving it exposed, and much of the light shines upward into the sky." When light can be concentrated where illumination is needed, and light pollution is reduced, allowing lighting to fulfill its true purpose, only then can we light the way home and give the Earth a clean sky.