What is the difference between a product-by-process claim and a claim with both product and process elements?

According to MPEP 2173.05(p), there is a key difference between these two types of claims:

• Product-by-process claim: This is a product claim that defines the product in terms of the process used to make it. It is considered proper and is not inherently indefinite. The MPEP states, “A product-by-process claim, which is a product claim that defines the claimed product in terms of the process by which it is made, is proper.”
• Claim with both product and process elements: This refers to a single claim that attempts to claim both an apparatus (product) and method steps of using the apparatus. Such claims are generally considered indefinite under 35 U.S.C. 112(b).

The key distinction is that a product-by-process claim is still fundamentally a product claim, while a claim mixing both product and process elements can create confusion about the statutory category of the invention and when infringement occurs.

To learn more:

• product-by-process claims
• mixed claims
• patent claim types
• indefiniteness