Why Need Ultrasonic Spray Coating For Optical Lenses?

Optical lenses are transparent optical components, mainly made of glass, plastic (such as resin) or crystal. They change the propagation path of light by refracting light to achieve the functions of focusing, diverging or correcting light. They are widely used in optical instruments, vision correction and various optoelectronic devices.

Ultrasonic spraying technology provides a highly efficient solution for applying functional coatings to optical lenses. It uses high-frequency ultrasonic vibrations to atomize the functional coating into uniform, micron-sized droplets. These droplets are then precisely deposited onto the lens surface via a low-pressure airflow, resulting in a functional coating with controllable thickness and uniform distribution. The key reason for choosing ultrasonic spraying equipment for optical lenses is that it precisely addresses the optical performance and production economics requirements that traditional technologies struggle to meet. It is particularly well-suited to the combined demands of high-end lenses for coating uniformity, minimal damage, and cost control.

 

1. Focusing on Optical Performance: Meeting Core Lens Specifications
Ultimate Uniformity, Avoiding Optical Defects: Optical lenses require extremely high coating thickness tolerances (required to be within ±2%) and surface roughness (Ra ≤ 0.1nm). Ultrasonic spraying uses high-frequency vibrations to produce uniform droplets of 5-50 microns. Deposition occurs without high-speed airflow, eliminating the "orange peel" texture associated with traditional air spraying and the "edge marks" associated with dip coating. This ensures a consistent refractive index across the coating and prevents light transmission distortion caused by localized thickness variations.

 

Low-damage process, substrate protection: Mainstream optical substrates such as resin and PC (e.g., for children's lenses and VR lenses) have poor heat resistance. Traditional vacuum coating requires temperatures exceeding 200°C, which can easily cause substrate deformation. Ultrasonic spraying is performed entirely at room temperature and low pressure, preserving the substrate's transmittance and physical strength, while avoiding damage to optical properties caused by high temperatures.

 

2. Optimizing economic efficiency from a production efficiency and cost perspective: High paint utilization, reducing raw material costs: Optical functional coatings (e.g., AR coatings) often contain nanoparticles or precious metals, resulting in high unit prices. Traditional air spraying has a utilization rate of only 30%-50%, resulting in significant paint waste due to rebound. Ultrasonic spraying, on the other hand, boasts a utilization rate exceeding 95%, directly reducing raw material consumption by 30%-50%, resulting in significant cost advantages in long-term production.
Low maintenance costs, reduced downtime: Traditional printheads are prone to clogging due to high-solids content coatings (e.g., anti-scratch coating slurry), requiring frequent disassembly and cleaning, resulting in short maintenance cycles and high wear rates. Ultrasonic nozzles are designed without tiny channels and rely on vibration-based atomization, making them less prone to clogging. Cleaning frequency is reduced by over 60%, reducing equipment downtime and improving overall production efficiency.

 

3. Application Flexibility: Adapting to Diverse Needs
Compatible with a Wide Range of Coatings and Lenses: Whether it's low-viscosity anti-fog coatings, high-solids anti-scratch coatings, or composite coatings containing nanoparticles (such as AR + anti-fingerprint dual-layer films), ultrasonic nozzles can reliably handle them. Furthermore, by adjusting spray parameters, they can accommodate lenses of various shapes, including round, square, and special shapes, eliminating the need for frequent mold or equipment changes.

Supports Precision Multi-Layer Overlay: High-end optical lenses often require multiple functional coatings (such as a three-layer structure for anti-reflection, anti-fouling, and wear-resistant coatings). Ultrasonic spraying allows for precise control of the thickness and composition of each layer, ensuring a tight bond between layers. This eliminates the delamination or performance degradation that can occur with traditional overlay technologies.

 

Coating Uniformity and High Precision: Ultrasonic atomization produces uniformly sized, micron-sized droplets that "float" onto the lens surface, avoiding uneven coatings, orange peel artifacts, and spattering. This makes it particularly suitable for the preparation of optical-grade thin films. For example, when applying AR (anti-reflection and anti-reflection) coatings, the coating thickness and composition can be precisely controlled to achieve excellent optical performance.

 

High Paint Utilization Rate: Traditional spraying methods result in significant paint waste, while ultrasonic spraying achieves a paint utilization rate of over 95%, significantly saving costs for expensive functional coatings.

 

Wide Applicability and High Flexibility: Ultrasonic spray nozzles are corrosion-resistant and resistant to clogging, capable of processing slurries containing nanoparticles or high solids content. Spraying parameters can be precisely controlled, adapting to lens shapes and sizes, as well as the preparation of multi-layer composite coatings.

 

Low Maintenance Cost and Environmental Protection: The nozzle design lacks fine channels, making it less prone to clogging, reducing cleaning and maintenance frequency and wear. Furthermore, due to reduced paint waste, environmental pollution is also minimized.