Patent family includes narrow sense and broad sense. In a narrow sense, patent family refers to the collection of applications for a patent in different countries. For example, we first apply for a patent in the United States, and then judge that the related technology or product may be sold to Japan and other countries in the European Union, and want to obtain the exclusive right to create the technology in that country, so we apply for a patent in that country or region. Therefore, the combination of the same patent invention content applied in different countries (usually based on the judgment of claims) is called narrow patent family.
Patent family in a broad sense refers to different applications derived from a patent, including division, extension and partial extension (CIP). That is to say, after the disclosure of the same technical invention (usually referring to the contents disclosed in the claims), different patent applications (other claims with different protection scopes) are constantly derived. Therefore, other inventions derived from the same technological invention, together with the patent portfolio of related patent applications in other countries, are patent families in a broad sense.