- VIC ultra-low-reflectance coatings for metals: a black-coating solution that Yamagata presents as the world's first to provide complete 360° coverage of complex internal optical surfaces.

Image: Surface Appearance After Anodizing and VIC Ion Coating

The process uses ion-coating equipment and proprietary polymer-based target materials to form a stable, hard, matte black nanostructured coating on aluminum alloys, including 6061, and on brass and other metals. According to Yamagata, the coating forms strong atomic bonds with the substrate, rather than relying solely on physical adhesion.

Reported performance includes a reduction in reflectance from 5% to below 0.3%, with light absorption exceeding 99.7%. Yamagata also reports a 50-fold reduction in reflectance compared with anodizing.

In cross-cut adhesion testing, the ion coating achieved ISO 2409 Class 0 and ASTM D3359 5B, the highest ratings under the respective methods. The cut edges remained intact, with no coating detachment observed. Conventional anodizing, by comparison, can leave exposed metal at electrical racking contact points.

Reliability testing showed no loss of performance after:

- 1,500 hours at 75 °C and 85% relative humidity.
- 1,000 hours at −40 °C.
- 1,000 thermal-shock cycles between −50 °C and +125 °C.

The technology also provides full 360° coating coverage. Internal bores, angled grooves, deep cavities and lens-barrel walls can all receive a uniform coating across the complex surfaces surrounding the optical path. This addresses the practical challenge of treating internal geometries that are difficult to coat effectively using conventional AR coating processes.

3. From Development to Volume Production

A technical breakthrough is only the beginning. Reliable volume production is what makes it commercially useful.

Yamagata Optical operates Class 10,000 cleanrooms for optical film components, with Class 100 clean workstations and more than 60 imported high-speed precision punching and die-cutting systems.

Its metalworking operation includes over 300 precision machines, including Swiss-type lathes and CNC turning centers. Together with VIC ion-coating systems, these provide an integrated manufacturing process from precision machining through ultra-low-reflectance surface treatment.

The company is certified to IATF 16949 for automotive quality management and has been recognized in China as a specialized, innovative enterprise. It holds more than 50 Chinese patents covering technologies such as chemical blackening of aperture edges, aperture-edge chamfering, serrated-aperture PET film components and composite light-absorbing coatings for baffle rings.

4. Five Key Application Areas

The range of applications for VIC ion coating continues to expand.

Smartphones and Consumer Electronics

Ultra-low-reflectance coatings are applied to lens barrels, lens mounts, spacer rings, baffle rings, shims, zoom actuators and mechanical shutters. They substantially reduce stray light, improve optical signal-to-noise ratio, suppress halos and light streaks, and enhance image quality.

Machine Vision and Inspection

Suppressing stray-light interference is essential to reliable machine vision and automated inspection.

LiDAR and Precision Optical Instruments

Spectrometers, fluorometers, high-resolution microscopes and intracavity laser optics can benefit from ultra-low-reflectance ion coating. Benefits include higher-quality images, more accurate data, reduced computational correction and simpler optomechanical designs.

Biomedical Imaging

Ultra-low-reflectance coatings are being adopted in endoscopes, ophthalmic microscopy systems, brain-imaging equipment, CT detector windows, microvascular imaging and other medical optical systems. By improving the visibility of lesions, they support accurate diagnosis.

Renewable Energy

Antireflection surface treatments for solar panels and concentrator photovoltaics (CPV) help increase power output. Yamagata describes these renewable-energy treatments as offering greater weather resistance than conventional sol-gel coatings, with a service life exceeding 25 years.

5. Beyond Aluminum: Expanding the Range of Substrates

With aluminum-based ultra-low-reflectance technology in stable volume production, Yamagata Optical is extending its capabilities to other materials. The company has already achieved advances on copper, stainless steel, ceramics and plastics, supported by long-term joint research with the Chinese Academy of Sciences and materials-science institutes at leading Chinese universities in the Double First-Class initiative.

These developments open the way for ultra-low-reflectance coatings on an increasingly broad range of optical components and substrate materials.

6. Optical Innovation from China, for the World

Twenty years ago, Yamagata Optical began as a small supplier of electronic materials. Today, it is a global leader in precision optical components and ultra-low-reflectance technology. From Tesla to Volvo, and from automotive cameras and medical endoscopes to consumer electronics and space exploration, Yamagata's technology offers comprehensive stray-light suppression for the global optics industry.

The company's values are simple: put customers first, focus on craftsmanship, keep innovating, and act with integrity and mutual respect. Two decades of development demonstrate a powerful idea: in optics, deeper black can enable brighter innovation.

Yamagata Optical exhibited at the China International Optoelectronic Exposition (CIOE) in Shenzhen in September 2025 and at the optoelectronics exhibition in Yokohama, Japan, in April 2026. The company plans to exhibit in Munich, Germany, in 2027, presenting its full portfolio of VIC ultra-low-reflectance ion coatings and technical solutions and discussing the future of ultra-black optical technology with the international photonics community.

Yamagata Optical: Stop Stray Light. Reveal the Image.