Patent inventors are the individuals who created the idea and wrote the patent. They may be the owner of the patent as well, but frequently the patent is owned, or assigned to, the university or business the inventors work with.
Patent Assignee is a field in the patent. This lists the original entitly the patent is assigned to when it is first published.
Patent Owner is the current owner of the patent. It may be the original assignee, the inventor, or another company or individual who has purchased the patent or has had the rights transfered to them.
When searching patents owned by a company, search in the Assignee field. You may need to search reassignments for older patents.
