Uniform 20 μm Phosphor Thin‑Film

Uniform 20 μm Phosphor Thin‑Film: Ultrasonic Coating for Small‑Caliber Quartz Tubes

Quartz tubes are widely used in precision optoelectronic devices, optical sensing elements and luminescent component manufacturing due to their excellent light transmittance, high temperature resistance and chemical inertness. The preparation of uniform and controllable phosphor thin films on the inner wall of quartz tubes is a core process to optimize the luminescence performance and optical stability of optoelectronic components. Traditional coating methods such as dipping and high-pressure spraying are difficult to adapt to small-diameter quartz tube processing, with common defects including uneven film thickness, residual bubbles and dead spraying areas, which seriously affect the yield and performance of precision optical devices. Ultrasonic coating technology has become an ideal solution for inner wall precision coating of small-caliber quartz tubes by virtue of its precise atomization and uniform film-forming characteristics.

This paper focuses on the precision coating process for quartz tubes with an inner diameter of 2mm. The ultrasonic coating equipment atomizes the configured phosphor solution into uniform micro-droplets through high-frequency ultrasonic vibration, and evenly sprays the droplets on the inner wall of the quartz tube to form a high-quality functional coating with a precise thickness of 20 microns. Different from traditional spraying technology that relies on air pressure to push liquid, ultrasonic atomization generates tiny, uniform and low-kinetic energy droplets, which can fully penetrate the narrow 2mm inner diameter of the quartz tube and cover the entire inner wall without dead angles.

The whole ultrasonic coating process is standardized and divided into four key stages: substrate pretreatment, solution configuration, ultrasonic spraying and film curing detection. Substrate pretreatment is the primary guarantee for high-quality coating. The 2mm inner diameter quartz tubes are cleaned by ultrasonic cleaning and high-purity solvent washing, then dried at a constant temperature to completely remove surface dust, oil stains and residual impurities. A clean and smooth inner wall substrate effectively improves the bonding force between the phosphor coating and the quartz tube, and avoids film peeling, light scattering and other defects caused by impurities.

In the solution configuration stage, the phosphor solution is strictly adjusted for viscosity and solid content to ensure uniform particle dispersion without agglomeration and precipitation. Stable solution performance is the basic condition for realizing 20μm fixed-thickness coating. In the core spraying stage, the equipment accurately adjusts atomization frequency, spraying flow rate and tube moving speed to control the deposition amount of phosphor droplets per unit area, so as to realize uniform accumulation and film formation of the coating.

After spraying, constant-temperature curing treatment is carried out to stabilize the internal structure of the coating, enhance the compactness of the thin film, and eliminate micro-bubbles and pinholes in the coating. Finally, multi-point thickness detection is performed on the inner wall of the quartz tube with professional precision testing instruments to ensure that the overall coating thickness is stably controlled at 20 microns with extremely low thickness deviation.

Compared with traditional processes, ultrasonic coating technology has outstanding advantages in small-caliber quartz tube processing. It realizes precise customization of 20μm ultra-thin uniform coating, solves the problem of uneven coating in narrow inner walls, and improves the yield of precision optical components. In addition, the technology has low material loss and high solution utilization, which reduces production costs while ensuring stable optical performance of the coating. With the continuous upgrading of precision optoelectronic manufacturing standards, ultrasonic coating technology will be more widely used in the field of functional thin film preparation of optical precision components.

About Cheersonic

Cheersonic is the leading developer and manufacturer of ultrasonic coating systems for applying precise, thin film coatings to protect, strengthen or smooth surfaces on parts and components for the microelectronics/electronics, alternative energy, medical and industrial markets, including specialized glass applications in construction and automotive.

Our coating solutions are environmentally-friendly, efficient and highly reliable, and enable dramatic reductions in overspray, savings in raw material, water and energy usage and provide improved process repeatability, transfer efficiency, high uniformity and reduced emissions.

If you have any technical questions, customization demands, or procurement inquiries about ultrasonic atomization nozzles, feel free to contact our professional sales and technical team for detailed parameters, customized solutions, and industry application support.
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