An evaporation model of a water droplet on a glass substrate is developed to estimate the process time needed to manufacture a liquid crystal display panel (LCD). By using an infrared (IR) lamp as a radiation source to evaporate the droplet, the changes in droplet size and evaporation time are calculated. The peak wavelength of the lamp and initial droplet size are used to estimate the process time. A change in the distribution of droplets is calculated to practically apply the model used in the drying process. By analyzing the contributions of radiation and conduction, we found that the evaporation process is driven by different heat transfer mechanisms according to the peak wavelength of the lamp.