Not every LED chip delivers what it promises; looks can be deceptive and incorrect handling can quickly degrade a LED's claimed characteristics. Zumtobel's Quality Assurance operates at two levels: on the one hand, only tested LED chips that meet the brand's exacting requirements are used. The second aspect of our QA is extensive quality testing and careful design and manufacture of LED modules. This underpins tried-and-tested Zumtobel quality that comes with a five-year guarantee.
Low-quality control gear (drivers) can have similar damaging effects due to unacceptable current spikes. Keeping colour rendering and colour temperature as stable as possible throughout an LED light source's entire service life is a huge challenge. Zumtobel deploys the very latest technologies such as Pi-LED which meets strict criteria that specify a precise colour in MacAdam ellipses. The smaller this deviation, the better the result is.
The International Commission on Illumination is therefore working on a new index and Zumtobel is supplying data obtained from in-house research studies for this work.
Ra 80 means that 80% of colour information is reproduced by the light source, this meets standard requirements for office and industrial applications.
Colours should be rendered as naturally as possible by choosing the corresponding phosphor mixes. Unfortunately, the efficiency of warm white LEDs is usually lower than that of intermediate and cool white LEDs. For a cooler colour temperature, the phosphor mix is changed. LEDs with cooler light colours are usually more efficient, but their colour rendering index is also lower. By mixing white light through LEDs of different light colours, excellent colour rendering can be achieved with simultaneously high efficiency.