The invention provides a method of pattering a substrate, in which a first material in solution is deposited on the substrate. A start-of-frame token sent by the USB host is used as a 1-ms reference cycle so that a high-frequency clock passes through the frequency divider to issue a first clock. A lower grate is supported at the lower opening of the middle member for holding material to be burned. When a shutter button is operated, the object scene is photographed in accordance with a set photographing mode. The preferred DATP protocol is portable for all STBs since it is written in a native language that interfaces with the underlying operating system of the STB. More specifically, lower dosage strength imiquimod formulations to deliver an efficacious dose of imiquimod for treating actinic keratosis with an acceptable safety profile and dosing regimens that are short and more convenient for patient use than the dosing regimen currently approved by the U.