Patents are valuable because they give the inventor the right to exclude others from making or using the patented invention. This right can be transferred to others through an assignment. Agreements to assign patents are common in industries that engage in research and development.
Most employment contracts with universities and tech companies include a provision that requires employees to assign the rights to anything they invent during the duration of their employment to the employer. These agreements often include inventions made by the inventor on her own time. Such far-reaching assignment agreements prevent employees from competing with their employer. Industry would have less incentive to produce new products if employees retained the rights to the inventions.
Formalities During Filing
The inventor -- or more commonly his employer -- files Form 1595 with the United States Patent and Trademark Office listing particular patents or patent applications that are subject to the assignment agreement. This record puts the world on notice that ownership of the rights to the intellectual property has been assigned to a particular company.