When does an improvement patent require (or not require if that&#39;s easier) a license from the holder of the original patent?
<p>first post here! I was curious when an improvement patent requires a licensing agreement with the holder of the original patent? I did some preliminary research, but everything I can find online is pretty vaguely worded. If you need more specifics to narrow scope, I'm asking in regards to a design patent on a software.</p>

<p>A patent owner's rights are defined by the claims in the patent. Some improvements just add to what is defined in a claim. The patented item has an A, a B, and a C. Your improvement has an A, a B, a C, and a D. By being a superset of the old thing, you fall under the definition of the old thing so you need their OK. If you find away to make it without a C, then you do not fall under that claim. Many improvements solve the problem a completely different way and do have A, or B or C at all. Patents do not cover what is achieved, they cover the way it is achieved.</p>

software patents