What does the so-called patent application have the principle of singularity mean?

The principle of singularity in patent application means that the parties applying for an invention, utility model or design should be limited to one invention, utility model or design, and cannot apply for the same patent for different types of inventions.

legal ground

Article 31 of the Patent Law of People's Republic of China (PRC) An application for a patent for an invention or utility model shall be limited to one invention or utility model. Two or more inventions or utility models belonging to a general inventive concept may be filed as one application. An application for a patent for design shall be limited to one design. Two or more similar designs of the same product, or two or more designs of products used in the same category and sold or used in sets, may be filed as one application. Article 32 An applicant may withdraw his patent application at any time before being granted the patent right.