Application of Tsingcarbo® Black Light Absorbing Coatings on Internal Structures of Opto Mechanical Systems

In optical imaging systems, stray light acts like a cunning “light thief”—it comes uninvited, yet it can ruin a meticulously designed image. Many people focus stray light control on the front end of the lens, such as adding lens hoods or optimizing coatings, but internal light absorption within the opto-mechanical system is equally critical.

The internal structure of an opto-mechanical system is far more complex than it appears. Components such as lens holders, apertures, baffles, and mechanical fasteners are full of irregular surfaces, threads, steps, and sharp corners. Every structural transition can become a natural hiding place for stray light. When light enters the system, not all rays obediently follow the designed optical path. Some rays reflect off these internal surfaces and eventually reach the image plane, producing ghost images, flare, or globally reducing image contrast and saturation.

What makes it even more challenging is that conventional stray-light suppression methods may have limitations inside opto-mechanical systems. The limited space can make spray painting with black coating difficult; black oxidation may offer limited absorption; and black velvet does not easily conform to complex 3D shapes. Once a single internal surface reflects light, some of the precautions taken on the outer layers may be affected.

The Tsingcarbo® Black internal light absorption solution is designed specifically for this main battlefield. It offers a hemispherical reflectance of ≤1.5%, absorbing more than 98.5% of stray light and cutting off the reflection chain at its source. Two processes are available: film lamination and spray coating. Our light absorbing film is flexible, making it suitable for flat or slightly curved surfaces, grooves, steps, and other irregular geometries – achieving absorption of over 99% (reflectance <1%) where applicable. Spray coating reaches into tiny channels and small recesses that cannot be laminated. The material itself is clean, non outgassing, and does not contaminate optical elements under vacuum or high temperature conditions, meeting the stringent requirements of precision opto mechanical systems.

From the retaining ring to the lens barrel, and then to the internal opto mechanical structure, three layers of defense work progressively to maximize stray light suppression.