Focused lighting with highly transparent silicone

The excellent mechanical and photophysical properties of silicone are exploited to the maximum in the innovative  RMJ  mixing dome. Together with its customer Bartenbach, starlim//sterner, the silicone specialist from Marchtrenk in Austria has developed an innovative new optical attachment for LED lights that ensures homogeneous distribution of light in every beam angle. The mixing dome creates lasting and unique lighting effects on both public and private buildings.

Located in the Tyrolean village of Aldrans, Bartenbach GmbH  has been developing lighting solutions for over 30 years, with a skilled team of 75 specialists drawing upon a wealth of expertise in every significant stage from light planning and design to development of its own and customised lenses. In addition to targeted illumination and lighting of spaces and surfaces, this provider always considers the physiological and psychological impact of a lighting concept on behalf of its customers. Research and development are, of course, of paramount importance. “We value our long cooperation with starlim//sterner very highly. It's a perfect combination of silicone injection moulding experience with our light design expertise, continually producing unique, innovative product solutions”, emphasises Christian Reisecker, Project Manager at Bartenbach. The latest product of this cooperation is the RMJ mixing dome. Now available on the market, this highly transparent silicone optical attachment offers enormous advantages.

Lenses are light-diffusing elements that, as in this case, are positioned in front of LED chips and ensure light diffusion and homogenisation through reflection or refraction. In contrast to conventional solutions such as PMMA or PC elements, the adhesive force of the silicone lens means it clings to the LED module like a seal, simultaneously providing protection against all external influences. Silicone also possesses electrically insulating properties that provide touch protection. The enormous UV and heat resistance of the material means that the proximity to the light source is completely uncritical in this regard. The silicone type selected for this special application is highly transparent, has transmission properties comparable to glass and does not yellow in the long term.


A high-end silicone optical attachment has been developed in cooperation with Bartenbach which is extremely thin and distinguished by undercuts and additional freeform surfaces of the highest quality and dimensional accuracy. “Our core competencies include being a co-designer and developer for our customers and partners. Aside from jointly selecting the best material for the application, we also cooperate to develop an optimum component and mould geometry for mass production. We have also upgraded our machine technology to produce the polished microfacetted surface of the RMJ mixing dome which, in turn, ensures the desired lighting effect”, explains Thomas Setz, Business Area Manager at starlim//sterner.

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