Comment by kccqzy

Patents are supposed to protect the inventor’s interest. The trick is to divulge enough details to get protection, but not enough that competitors can just copy. So if a patent says “a hydrofluoric acid-based etchant” you can almost be sure that ingredients other than HF will be necessary in a fashion that’s not immediately clear until it is tried. The actual formulation will be a trade secret. What’s also unsaid is of course, the concentration of HF, the duration of exposing the glass to HF, the temperature at which this is done, the method of applying HF to the glass and the method to remove residue HF, etc.