The technical field of an invention or utility model shall be the specific technical field to which the technical solution of the invention or utility model for which protection is sought belongs or to which it is directly applicable, and not the superior or neighboring technical field, nor the invention or utility model itself.
This specific field of technology is often related to the lowest position in the International Patent Classification (IPC) in which the invention or utility model may be classified.
For example, an invention for an excavator cantilever is improved by changing the rectangular cantilever cross-section of the background art to an elliptical cross-section. The technical field to which it belongs can be written as "The present invention relates to an excavator, in particular to an excavator cantilever" (specific technical field), instead of "The present invention relates to a construction machine" (superior technical field), or as "The present invention relates to an excavator cantilever with an elliptical cross-section" or "The present invention relates to an excavator cantilever with an elliptical cross-section" (the invention itself).