LED Lighting Requires New Approaches in Optics

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Even though LED technology has been established LEDs still need new approaches in electronics, thermal management or optics to make complete use of their advantages. Marek Škereň, Chief Technology Officer of IQ Structures, explains how new optical devices, with the trade name Nanoptiqs, based on principles of diffraction are applied to achieve improved performance of white light illumination systems. This unique solution is based on full control over the modulation of material and geometric properties of the optical elements at a nano-level. A combination of complex transmission diffractive elements, with specially designed systems of micro-reflectors (produced using an innovative mass-production technique) is also presented as a promising flexible building unit for the construction of new generation luminaires. For a long period of time light from lighting systems was managed using conventional optical elements based on reflection or refraction. Large light sources required bulky optical systems, however, the beam shaping capabilities were rather low. It was almost impossible to achieve complicated light distribution curves (LDC), even for complex configurations of optical elements. An invention of LED based solutions for lighting applications introduced new degrees of freedom to the design of luminaires. The most important parameter from this point of view is the size of an LED chip, which is significantly smaller than the typical dimensions of conventional light sources. Generally, a small light-emitting volume enables miniaturization of optics and complete luminaires. However, the highest potential follows from a significant increase of spatial coherence of the emitted light. New approaches based on diffraction of light from micro and nano-structured materials can now be used for extended shaping of light distribution curves. Application of diffractive elements dramatically increases flexibility of the beam shaping process and enables precise illumination of areas with complicated shapes and requirements with a spatial distribution of energy. Such capability results are not only a significant improvement in the quality of illumination, but it can also lead to an important increase in overall efficiency of illumination systems and reduction of energy consumption. Moreover, in most cases the systems based on diffractive elements are lightweight, convenient for mass production and have lower environmental impact following from their production and disposal. The presented approach opens new interesting possibilities also for visual design of future light fixtures. The designers benefit from significantly higher flexibility of shapes of optical components. The complexity of the optical function is not any more closely connected with the complex geometry of the optical elements. Thus, smooth designs with simple geometric shapes can be used in combination with the sophisticated optical performance of the luminaire. Also, the geometric dimensions of light fixtures are positively influenced, extremely thin or narrow bodies can be constructed