For more than 20 years we have been successfully using our coating know-how in the medical device market. Our core competence lies in the integration of sapphire windows into optical medical analysis devices (hermetic packaging), for example for endoscopy. We produce among others solderable coatings and sterilization-resistant optical filters for camera systems.
The main disadvantage of sapphire crystal is its very high refractive index (1.77). This causes a high reflection of the incident light, greater than approx. 15% (approx. 7.5% per side).
The anti-reflective layers applied on one or both sides of the lens or sapphire window reduce this reflection in order to avoid the formation of ghost images and to maximize the intensity of the light signal transmitted through the endoscope.
Anti-reflective coatings are applied to both sapphire and mineral crystals. Blösch SA's portfolio is based on 5 anti-reflective layers used in the field of medical devices:
