Writing patent claims

Writing patent claims is analogous to describing multidimensional jigsaw puzzle pieces using words.  Your claims have to fit in the spaces between prior art.

Patent claims are the most important part of a patent because the claims are legally enforceable.  Claims are also the trickiest part because they have to follow many rules.  They should describe your invention, not read on the prior art, and not be obvious variations on prior art. Claims should also be precise enough that others can clearly determine what it is that you are claiming. They are also important for determining inventorship, and ownership. Here are some examples.

Patent claims are like a jigsaw puzzle:  

As a useful analogy, consider each claim to be somewhat like a multidimensional jigsaw puzzle piece. Each claim should be written using words and clauses. These must describe your invention. They must also “bend in” to avoid prior art. You can get stronger claims if you make them “bend out” when there is no prior art.

The patent examiner is looking at your claims in the context of the other prior art (the other pieces). They want to see if each of your particular claim “pieces” fits nicely into the holes between prior art. Your claim “piece” can’t hit the other prior art “pieces”.  If there is a hit, the examiner will reject until your claims “bend in more” to avoid that prior art.  When you write patent applications, you should to try to anticipate when this might happen. You should write the patent application in a way that gives you more flexibility to modify claims during examination.

There is one big difference over jigsaw puzzles, however.  In jigsaw puzzles, although the different pieces can’t overlap, the gap between the different pieces can be made very small.  In the patent world, however, we can sometimes run into trouble because of another rule that claims can’t be “obvious.” Is it obvious that if one piece is “bending in”, the other piece must “bend out?”

This is why examiners are sometimes uncomfortable with small “gaps.” They may want you to make the “gap” bigger to avoid obviousness issues.  So, during patent examination, you need to negotiate the extent of this gap, and amend your claims accordingly.

Patent law is complicated: 

Patent claims also have to satisfy many other criteria as well. They can’t be ambiguous, and can’t require undue experimentation. In litigation, method, system, and structure plus function claims have certain differences that can also be important.