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Radiation Curing of Coatings in Vacuum Environments

IP.com Disclosure Number: IPCOM000201178D
Publication Date: 2010-Nov-09
Document File: 2 page(s) / 47K

Publishing Venue

The IP.com Prior Art Database

Abstract

This disclosure discusses the construction of an array of UVLEDs provided with a cooling design that is easy to implement in a vacuum system.

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Radiation Curing of Coatings in Vacuum Environments

It is known to use ultraviolet light emitting diodes (UVLEDs) cure coatings in atmospheric pressure conditions. It is also known that for some radiation-curable materials, the curing process is advantageously carried out in a purged environment to prevent oxygen inhibition of the curing reaction. However, commercial UV sources are designed for operation at atmospheric pressure, and there are considerable barriers to operating them in vacuum systems. Foremost, they generate considerable heat and need to be cooled - typically by forced flow of air, inert gas, or water over the lamps - to keep them at the correct temperature for efficient emission of UV light. In vacuum, the lamps and the external surfaces of the lamp housing become hot due to the lack of convective (natural or forced) cooling around the housing. The heat can damage the lamp, and the hot external surfaces can radiate heat to the substrate and coating, sometimes causing damage to the substrate or defects in the coating. The present disclosure discusses the construction of an array of UVLEDs provided with a cooling design that is easy to implement in a vacuum system.

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Figure 1

Figure 1 depicts a UVLED array according to the present disclosure. It was fabricated from 264 chip-type 390 nm UVLEDs commercially available P/N NCSU034A from Nichia Corp. of Tokyo, Japan. The UVLEDs were mounted on a Metal Clad Printed Circuit Board (MCPCB) commercially available from Bergquist company of Chanhassen, MN. The MCPCB assembly was mounted on a water cooled heat sink commercially available from Aavid Thermalloy LLC of Concord, NH. The active area of the array was 5 inches by 13 inches, and the nominal operating voltage was 43 volts at 10 amps.

A vacuum chamber for performing the vacuum deposition of organic monomer was prepared, the chamber having a large chill drum and a...