Significant reductions in energy consumption are essential if the drive to reduce greenhouse gas emissions and fight climate change is to be successful. Wall-to-wall deployment of energy-efficient LEDs and energy-saving lightbulbs along with a combination of LEDs with smart light management systems are important steps in the right direction. Whereas the use of LEDs and energy-saving lightbulbs is increasing steadily, the benefits of efficient light management systems for LEDs remain largely untapped.
The aim of the "INTENSE" research project undertaken by the Fraunhofer Institute for Production Technology IPT in collaboration with four partners from industry, is to develop a process chain capable of manufacturing smart optical components for efficient light management systems.
The project involves two separate areas of interest: Light control and light direction. Light control encompasses gathering information and regulating lighting, whereas light direction is responsible for illuminating specific areas of the room as required. Most conventional, commercially available motion sensors used in light control systems consist of only one infrared-sensitive pixel and react to changes in the infrared (IR) heat. Consequently, control is purely binary (on/off). Neither the nature of the motion detected nor its position in the room are recognized. Efficient use of light, however, depends on a more detailed view of the situation.
In the "INTENSE" research project, a system incorporating an infrared sensor matrix is being developed to ensure precise motion detection. This system lighting to be switched as required over the entire area covered by the sensor system.
Light direction is the second arm of any efficient light management system. In addition to an optical sensor system, a structured polymer lens suitable for use in both diffuse and targeted light distribution is being produced. The optic is produced by injection molding which permits specific lighting conditions to be set depending on the requirements and application concerned.
The manufacture of infrared sensors for the motion detector presents a particular challenge. The use of chalcogenide glass, a material which is transparent in the infrared spectrum is an economical and resource-saving approach. However, chalcogenide glass has a high refractive index, associating with high reflection and the resultant transmission losses. To reduce reflection and transmission losses, chalcogenide glass optics are frequently coated with antireflective materials. Unfortunately, in addition to increasing the production time, these incur additional costs and often involve the use of environmentally unfriendly substances.
At the Fraunhofer IPT, the optics are not coated with anti-reflective materials; instead, a moth-eye structure is applied to the optics. In the course of this process, isothermal precision glass molding techniques are used to produce anti-reflective nanostructures like those on the eyes of nocturnal moths on the optics. In conjunction with the wear protection coatings developed at the Fraunhofer IPT, the isothermal precision glass molding operation, is particularly suitable for manufacturing optical components with complex geometries and provides higher scalability than conventional manufacturing techniques such as grinding and polishing.
Energy consumption and economic outlay will be validated and quantified over the entire project duration in order to quantify the potential for energy and cost-related savings in optics manufacture as well as during the service life of the light management system. Detailed analyses will be conducted on parameters and scenarios related to the use and disposal phases of light management systems. The focus in this period will be on identifying additional energetic and economic potential for optimization both within individual sub-processes and between the sub-processes as well as on comparing this process with conventional process chains.
German Federal Ministry for Economic Affairs and Energy (BMWi)
Lead partner Research Center Jülich GmbH