[OSM-talk] It's all over! (patent fun)

[David Earl]

Oh, and one other thing: if there is a valid patent on invention B, you 
can't claim a patent on invention A where A is smaller part of B, 
because that would already be covered by B. However you can claim a 
refinement of B, C say. (Of course to make use of C, you would have to 
license B as well if you aren't the patent holder and B is still current).

Most patents are like this: small incremental steps on previous 
inventions, and part of the originality test is whether the new bit is 
sufficiently different.

And one more thing: I said the description of a patent doesn't matter so 
far as its validity is concerned. There is one exception: if the claims 
are phrased as "I claim a means to do something", that is legalese which 
means that the scope of the claim is precisely limited only to the 
invention as described in the body of the patent. That doesn't apply in 
this case.

David