Thin Film Coatings

Thin Film Coating Performance - Advanced Thin Film Technology

Optical coatings are ultra-thin layers deposited on optics to manage reflection, transmission, polarization, and durability. There is a wide variety of thin film coatings, each designed for diverse applications across industries. Thin film coatings are used in various fields such as electronics, optics, medicine, and research. In EO/IR systems, thin film coatings ensure high transmission and long-life protection for lenses, sensors, mirrors, and windows got.

Thin films play a critical role in both active and passive devices. Our team engineers thin film coatings that meet tight film thickness tolerances while withstanding shock, vibration, humidity, sand, and salt spray. The ability of different materials to form stable thin film coatings is crucial, as it impacts manufacturing efficiency and stability. Thin film coatings are also used to improve the mechanical, optical, and environmental properties of devices.

Examples of thin film coating applications include anti-reflective anti-scratch, and polarization coatings.

We employ multiple coating methods including thin film deposition by chemical vapor deposition, ion-assisted carbon, spin coating, and dip coating. Each coating process is selected based on the target material, the substrate, and the required coating thickness.

Optical Coating Design & Verification

Our in-house team designs our thin film methods and formulas that spans the multispectral environment which includes UV, visible, NIR, SWIR, MWIR, and LWIR with oxides, metals, and select rare-earth materials to tune spectral bands. We model thin film deposition techniques to manage morphology, surface adhesion, mechanical properties (stress, hardness), and layer uniformity while minimizing coating defects. The optical properties of thin films are determined by their refractive index, extinction coefficient, and structural features. Selecting the appropriate deposition technique is essential for achieving desired film properties.

Performance of your coating depends on:

  • Processing discipline (cleanliness, fixturing, bakeouts)
  • Number of layers and tight film thickness tolerances
  • Refractive-index contrast and surface diffusion behavior
  • Matching coating material to the substrate (e.g., germanium vs. sapphire)
  • Thin film morphology which describes the structural characteristics of thin layers of material, encompassing aspects like surface roughness, internal void networks, and the overall arrangement of grains and columns.
  • The requirement for precise temperature and chamber conditions for high-quality coatings.
  • The microstructures of thin films, such as grain boundaries and dislocations, are critical to their performance. These microstructures are characterized using advanced microscopy and diffraction techniques.

We validate designs through in-line and post-process deposition process checks, spectral verification, and environmental screening.

Critical Pre- and Post- Coating Steps

Precision Cleaning

We begin with automated ultrasonic lines to deliver a meticulous substrate surface that promotes adhesion and long-term reliability.

Inspection & Standards

Each deposited film is inspected to ANSI, MIL-SPEC, and ISO 10110. This replaces guesswork with standardized acceptance criteria and traceable quality records.

Protective Coatings: DLC & Hard Carbon Coating

Clear Align produces coatings such as diamond-like carbon (DLC) and other hard coatings. These coatings manage thickness to protect windows against abrasion, salt spray, and particle impacts. These advanced coatings provide improved durability and performance for optical surfaces. The advantages of using advanced coatings include enhanced protection and longer service life for critical components.

We also offer anti-reflective coatings to reduce Fresnel loss across the visible range and infrared. These AR coatings are improving the reliability and image quality of optical systems by minimizing unwanted reflections and enhancing light transmission. Ion-assisted thin film deposition processes produce uniform film coatings on flat and curved optics, and our AR portfolio is tailored for ISR payloads, laser systems, and high-NA assemblies.

AR Coatings & Spectral Filters

Our AR portfolio reduces Fresnel loss and ghosting across the visible and infrared. Ion-assisted processes, crystal monitoring, and real-time rate control deliver uniform film coating on flat and curved optics, with custom tooling for complex geometries.

Our optical coatings include notch filters that block specific wavelengths while passing others, critical for laser safety, microscopy, and security applications. Custom designs are developed for multi-band operation across UV to LWIR.

Precision at Scale

We support prototype to production with multi-chamber capacity and in-house spectrophotometry to keep spectral bands, layer thickness, and adhesion in tolerance. Scaling thin film production is essential to meet increasing manufacturing demands while maintaining consistent quality. Our manufacturing processes and careful control of deposition parameters directly influence the microstructure and properties of the final thin films. Deposition rates are closely monitored and controlled to ensure film quality, process efficiency, and stability throughout production. Our tooling library have over 30,000 custom fixtures and we have an in-house machine shop for quick fixture designs on quick-turn programs.

Chalcogenides, Specialty Glasses and Military Optics with Unique Requirements

We apply deep expertise in the basic properties of thin films and the surface science of specialty chalcogenide substrates. Our team maintains precise control of vacuum chamber conditions and deposition temperature to ensure uniformity in advanced coatings for mass production. When working with specialty materials, the requirement for precise control of temperature and chamber conditions is critical to achieve high-quality optical coatings. The formation of thin films often involves chemical reactions or vapor deposition techniques. Clear Align works with a wide range of glass substrates and delivers both metallic films and custom films deposited, including tank windows and other specialty optics engineered for extreme environments.

Flawless Results: Advanced Automated Cleaning Systems

We are experts in depositing thin films on bulk materials, and it begins with automated ultrasonic cleaning that provides a meticulous surface for optical coatings.  This process is critical to adhesion and long-term reliability. 

Optical Coatings Inspection

Our coating process utilized modernized inspection techniques and equipment and inspect to ANSI, MILSPEC, and ISO 10110 standards. Film thickness is measured using various techniques to ensure quality and consistency throughout the deposition process. The elemental composition of thin films is studied using advanced analytical methods such as X-ray photoelectron spectroscopy. This disciplined process eliminates guesswork for inspectors and offer standardized quality control whether spherical or flat substrates.

Unique Capability: Advanced Dual-Band, Broadband, and Multiband Coatings 

Our expertise in thin film technology extends to specialized dual-band, broadband, and multiband optical coatings. These film coatings provide transmission across short wavelength infrared (SWIR), mid wave infrared (MWIR), long wave infrared (LWIR), and visible light, supporting free-space optical communications, ISR platforms, and multi-sensor fusion.

In addition, thin film coatings are widely used in solar cells to enable efficient energy conversion, leveraging advanced materials for enhanced performance in renewable energy systems. Thin film batteries also benefit from these coatings, making them thinner and lighter for use in compact electronic devices and medical implants. The addition of new functionalities and properties through advanced thin film coatings further expands their applications in various technological fields.

Effect of Coating on Center Thickness

Thin films grown can modify your lens center thickness and that will vary with wavelengths. The resulting changes in lens thickness after coating deposition depend on the specific coating materials and processes used. Please note we measure CT prior to coating. Coatings typically have minimal effect on center thickness for shorter wavebands such as Visible and SWIR, as these coatings are thinner and may have no effect, while LWIR and MWIR can be thicker, and this should be taken into account during your design phase.

Partner With Clear Align

Clear Align offers decades of expertise. Let’s build coatings that perform where it matters most—contact Clear Align today to start your program

Qualification and Inspection Available:

  • 8.1 MIL-M-13508C: Military Specification - Mirror, Front Surfaced Aluminized for Optical Elements
  • 8.2 MIL-F-48616: Military Specification - Filter (Coatings), Infrared Interference: General Specification
  • 8.3 MIL-C-48497A: Military Specification - Coating Single or Multilayer, Interference Durability Requirements
  • 8.4 MIL-C-14806A: Military Specification - Coating Reflection Reducing for Instrument Cover Glasses and Lightning Wedges 
  • 8.5 MIL-C-675C: Military Specification - Coating of Glass Optical Elements (Anti-Reflection)
  • 8.6 MIL-PRF-13830B: Optical Components for Fire Control Instruments; General Specification Governing the Manufacture, Assembly, and Inspection
  • 8.7 MIL-STD-810G: Department of Defense Test Method Standard: Environmental Engineering Considerations and Laboratory Tests 
  • 8.7.1 MIL-STD-810C
  • 8.7.2 MIL-STD-810D
  • 8.7.3 MIL-STD-810E
  • 8.7.4 MIL-STD-810G 
  • 8.8 ISO 9211-3: Optics and Optical Instruments - Optical Coatings - Part 3: Environmental Durability
  • 8.8.1 Application Categories and Recommended Tests for Environmental Durability
  • 8.8.2 Thermal Cycle Acceptance Tests According to the Standard
  • 8.9 TS-1888: Technical Specification for Infrared Optical Coatings

Clear Align routinely fabricates and coats these materials and many others:

  • Acrylic(PMMA)
  • AMTIR
  • Barium Fluoride (BaF2)
  • Brass
  • Bronze
  • Calcium Fluoride (CaF2)
  • Chalcogenide Glass (IRG, IG)
  • Copper
  • Fused Quartz
  • Fused Silica
  • Gallium Arsenide
  • GASIR (calcogenized glass)
  • Germanium (Ge)
  • Gold (Au)
  • GRIN
  • IRG24
  • IRG26
  • Indium Antimonide
  • Lithium Fluoride
  • MgF2
  • MS Zinc Sulfide (Cleartran)
  • N-BAK1
  • N-BAK4
  • N-BK7
  • Nickel
  • N-SF10
  • N-SF11
  • N-SF2
  • N-SF5
  • N-SF8
  • N-SK11
  • OPK
  • PMMA
  • Polycarbonate
  • Polymers
  • Polystyrene
  • Rexolite (Polystyrene)
  • Sapphire
  • Silicon
  • Silver
  • Zeonex (E48R, 480R, 480)
  • Zeonex Aluminum
  • Zinc Selenide