Use of Radiochromic Labels for UV Process Control

摘要

Lamp monitoring is a critical process control parameter for a UV cure process in a production environment. In many cases, however, equipment design does not allow conventional radiometers to be used so alternatives must be found. A common method is to use a film or paper strip coated with a UV sensitive dye that undergoes a photochemical color change upon exposure. The extent of the color change can be correlated with the exposure conditions. The observable, in this case the color change, gives no information on the spectral distribution of the light source or the action spectrum of the dye chemistry and extreme care must be taken when this information is used to control a process. We have found that despite these limitations, radiochromic tags of this type can be very useful under the right conditions and provide extremely reliable process control information.