Provide a valuable resource to your clients or customers by linking to this resource page. Just place the following link on your website.
A hard dip coating is a method of applying a scratch-resistant layer to a spectacle lens. The lens is fully immersed (dipped) into a liquid hard coat solution and then slowly withdrawn. This process coats the entire lens surface with a uniform layer of protective resin.
read more about hard dip coating on eyeglass lenses ...The main purpose is to increase surface hardness. Plastic and polycarbonate lens materials are naturally soft and scratch easily. The hard dip coating provides a tough barrier that resists minor abrasion and scratching from cleaning and normal wear.
The lens is held by a specialized clamp and submerged in the liquid hard coat. It is then removed slowly and evenly. Gravity pulls the excess liquid off the surface, leaving a perfectly uniform coating layer, which is then cured with UV light or heat.
Dip coating covers the entire lens uniformly at the same time. Spin coating applies the liquid only to one side and relies on centrifugal force to spread the liquid. Dip coating is slower but often results in a more robust coating across the entire lens curvature.
The hard coat is a foundational layer. Anti-reflective and other coatings must be applied over the hard coat. If the hard coat is missing, the sensitive AR coating would be applied directly to soft plastic, making the entire lens vulnerable to damage.
Yes, the hard dip coating is completely clear and does not affect the visual quality of the lens.
It is highly discouraged. A plastic lens without a hard coat would scratch almost instantly from minimal cleaning.
No, the hard dip coat provides scratch resistance. AR coating is a separate treatment applied later to reduce reflections.
Hard dip coating protects the lens from microscopic debris. If your lenses have thousands of fine scratches, they can scatter light, leading to "glare" and reduced contrast sensitivity at night. Consult your doctor to see if your lenses require replacement for safety.
FDA. Impact Resistant Lenses and Hard Coats (fda.gov). 2024.
ABDO. Spectacle Lens Materials and Coatings (abdo.org.uk). 2023.
The Vision Council. Lens Protection Standards (thevisioncouncil.org). 2024.
Review of Optometry. Advanced Lens Coatings (reviewofoptometry.com). 2024.