Ophir IR Optics 2024 Catalog

HE (High Efficiency) Coating Adhesion: per MIL-C-48497A paragraph 4.5.3.1 Humidity: per MIL-C-48497A paragraph 4.5.3.2 (24 hours) Moderate abrasion: per MIL-C-48497A paragraph 4.5.3.3 Temperature: per MIL-C-48497A paragraph 4.5.4.1 (2 hours) Temperature: per MIL-C-48497A paragraph 4.5.4.1 (2 hours) Solubility & cleanability: per MIL-C-48497A paragraph 4.5.4.2 HD (High Durability) Coating Adhesion: per MIL-C-675C paragraph 4.5.12 Humidity: per MIL-C-675C paragraph 4.5.8 (24 hours) Salt spray (fog): per MIL-C-675C paragraph 4.5.9 (24 hours) Salt solubility: per MIL-C-675C paragraph 4.5.7 (24 hours) Moderate abrasion: per MIL-F-48616 paragraph 4.6.8.3 Severe abrasion: per MIL-C-675C paragraph 4.5.10 (20 strokes) HC (Hard Carbon) Coating and LRHC (Low Reflection Hard Carbon) Coating Adhesion: per MIL-C-675C paragraph 4.5.12 Severe abrasion: per MIL-C-675C paragraph 4.5.10 (40 strokes) Humidity: per MIL-C-675C paragraph 4.5.8 (24 hours) Salt solubility: per MIL-C-675C paragraph 4.5.7 (24 hours) Salt spray: per MIL-C-675C paragraph 4.5.9 (24 hours) Temperature: per MIL-M-13508C paragraph 4.4.4 (-62°c-+71°c 5 hours each temp) Windscreen wiper action: no part of the coating shall show signs of removal when exposed to 5,000 revolutions of a wiper blade under 40 grams load using a sand (to defstan 07-55 type c) / water mixture. Chemical attack: the coating shall be inert to corrosive attack by acids etc. Specifically, the coating shall endure an acid immersion for 10 minutes in dilute HCL (0.1 normal HCL). Thin film coating durability Hard carbon vs. low-reflection hard carbon as external lens coatings The ideal external coating for lenses should have both high transmission and high durability to withstand harsh environmental conditions, such as extreme temperatures, high humidity, saline environment etc. However, there is a tradeoff between high transmission and high durability. While the most durable coating is hard carbon, its transmission is not the highest. As an example, the transmission of hard-carbon coating on Silicon, in the MWIR region of 3.4µm to 4.9µm wavelengths, is 93%. For higher transmission values, the low-reflection hard carbon coating is offered, which has a transmission of 97%. This coating, however, is less durable than the hard-carbon coating, especially in a maritime environment. Nevertheless, the LRHC coating still meets the MIL standard requirements from hard coatings as listed above. To conclude, in a case where most extreme environmental conditions prevail, especially humid conditions or maritime environment, hard-carbon coating is recommended. In all other cases we recommend using low-reflection hard carbon coating. 13 For latest updates please visit our website: www.ophiropt.com/infrared About Ophir 02-2024