What are Claims?

Claims are crucial, both for Validity and Clearance searches, and for writing your own patents. The Claims, and nothing else, are what determine exactly what material a patent covers. The BACKGROUND OF THE INVENTION may discuss all sorts of related technologies and inventions, and the DETAILED DESCRIPTION may suggest 101 different uses for, or implementations of, the invention. But, if it is not in the Claims, it doesn't count. (OK, that is a bit of an over-simplification due to the Doctrine of Equivalents and other legal issues, but if you understand those topics, you don't need to read this tutorial).

Patents have "independent claims" and "dependent claims". Dependent claims are those that refer back to a previous claim, and thereby may require that previous claim to be valid for themselves to be valid. For instance, let's use a fictitious bicycle patent. Claim 1 might read "A lighter, more aerodynamic design for a bicycle rim by using an oval cross-sectional shape". And Claim 2 might read "The rim of Claim 1 where the cross-sectional piece is formed from aluminum".

Thus, Claim 2 is dependent on Claim 1, because, as an extension of Claim 1, Claim 2 cannot exist without Claim 1. This is a very important concept in Validity searches, where it is a common strategy to attempt to invalidate mainly the independent claims, to potentially invalidate the dependent claims in the process.