Diamond-Like Carbon (DLC) coatings are advanced amorphous carbon coatings that combine key properties of diamond (high hardness and wear resistance) with some characteristics of graphite (chemical inertness and elasticity). This unique combination makes DLC coatings highly effective for optical, infrared, mechanical, and defense applications, where durability and long-term performance are critical.
In optical systems, DLC coatings are widely applied to lenses, windows, domes, and protective optical components, especially those exposed to harsh environments, abrasive conditions, or extreme temperature and humidity variations. DLC is particularly valued for infrared (IR) optics, as it provides strong environmental protection while maintaining excellent IR transmission.
Key Properties of DLC Coatings
- High Hardness & Wear Resistance: Typical hardness ranges from 10–30 GPa, offering excellent resistance to scratches, abrasion, and erosion.
- Low Coefficient of Friction: Reduces surface wear and minimizes particle adhesion, especially in unlubricated or vacuum environments.
- Chemical Inertness: Highly resistant to corrosion, acids, solvents, and harsh industrial chemicals.
- Environmental Stability: Maintains performance under UV exposure, temperature cycling, and humidity.
- Infrared Optical Transparency: Excellent transmission in the infrared wavelength range, making DLC ideal for IR lenses and windows.
- Hydrophobic Behavior (Optional): Certain DLC formulations provide moisture and fog resistance.
- Biocompatibility: Selected DLC variants are suitable for medical and biomedical applications.
DLC Coating Deposition Methods
DLC coatings are deposited in controlled vacuum environments to ensure high purity, adhesion, and uniformity.
- Physical Vapor Deposition (PVD): Uses sputtering or arc evaporation to deposit carbon atoms onto optical substrates with precise thickness control.
- Chemical Vapor Deposition (CVD): Deposits DLC films through chemical decomposition of hydrocarbon gases at elevated temperatures.
- Plasma-Assisted CVD (PACVD): A variant of CVD where a plasma is used to enhance the chemical decomposition of gases, leading to a higher quality coating at lower temperatures.
Coating Quality & Performance Criteria
For optical and infrared applications, DLC coatings must meet strict quality standards:
- Uniformity: Consistent coating thickness across the optical surface
- Adhesion: Strong bonding to substrates such as Ge, ZnSe, ZnS, silicon, chalcogenide glass, and fused silica
- Controlled Thickness: Typically from tens of nanometers to several micrometers, optimized for protection without degrading optical performance
- Surface Roughness: Maintained or post-polished to meet optical surface requirements
- Optical Transmission: Verified across the required wavelength range (especially IR bands)
Transmission Curve of DLC coating on Glass Substrate
Applications of DLC Coatings
- Optical & Infrared Components: Protective coatings for IR lenses, windows, mirrors, and domes used in thermal imaging, night vision, and IR spectroscopy systems.
- Military & Defense Optics: Applied on surveillance optics, targeting systems, missile seekers, and ruggedized field equipment requiring extreme durability.
- Automotive & Transportation Systems: Used on automotive cameras, LiDAR optics, and sensor windows for abrasion and environmental resistance.
- Scientific & Industrial Instruments: Protects lenses and windows in spectrometers, microscopes, and analytical systems exposed to chemicals or harsh environments.
- Medical Devices: Used on surgical tools and implants where wear resistance, chemical stability, and biocompatibility are required.
- Electronics & Precision Mechanics: Applied in hard disk drives, precision bearings, and moving components to reduce friction and wear.
Benefits of DLC Coatings for Optical Lenses
- Enhanced Scratch & Abrasion Resistance: Ideal for outdoor, military, and industrial optics
- Maintained IR Optical Clarity: No compromise to infrared transmission performance
- Chemical & Environmental Protection: Shields optics from corrosive agents and moisture
- Extended Component Lifetime: Reduces maintenance and replacement costs
- Improved Reliability in Harsh Conditions: Ensures consistent optical performance over time
Shapeoptics DLC Coating Expertise
Shape Optics Technologies provides advanced DLC coating solutions for optical and infrared components, supported by deep expertise in optical materials, coating design, and application-specific optimization.
Our team ensures each DLC coating solution is matched to the application, operating environment, and optical performance requirements, delivering long-term reliability and protection.