What is essential material in patent applications?

Essential material is defined in 37 CFR 1.57(d) as material that is necessary to:

• Provide a written description of the claimed invention as required by 35 U.S.C. 112(a)
• Describe the claimed invention in terms that particularly point out and distinctly claim the invention as required by 35 U.S.C. 112(b)
• Describe the structure, material, or acts that correspond to a claimed means or step for performing a specified function as required by 35 U.S.C. 112(f)

Essential material may only be incorporated by reference to a U.S. patent or patent application publication.

To learn more:

• essential material
• incorporation by reference
• patent application
• specification