While patent applications can only describe what is known at the time of filing, they exist in and for the future. First, the patent application is meant to protect a business/product which often does not yet exist. Second, the patent application, when granted, will be in force for ~20 years from the time of filing. Third, in most countries, no changes are allowed in a patent application except as specifically provided for and anticipated in the patent application as filed.
So, how can we draft a good patent application, if we are not aware of what market will be like, what prior art will come up, what the Examiner will misunderstand and what the competition will be doing?
The short answer is that we cannot. But we do have some techniques which can help.
First, we can make sure that what inventor does know or should know or can easily know, is extracted from the inventor and taken into account in the drafting. This is especially true about plans and thoughts for future R&D.
Second, we can leverage our experience as patent attorneys and try and predict the most likely directions examination and prior art might take.
Third, a careful analysis of the possible directions the market, product and competition might take should be carried out before filing.
Finally, the patent application should be refocused, as the future becomes clearer. This can often be done during responses to office actions or during times where a voluntary amendment is allowed.
So, are you protecting the past or looking to the future?