Patent documents, if grayscale views, color pictures, etc. are used, can easily become blurred during repeated printing and copying, and the patent features are no longer obvious, which is not conducive to patent application and transfer. , and subsequent patent protection, etc., and two-dimensional line drawings are concise and to the point, and have little chance of distortion in printing, copying, etc., so currently Europe and the United States generally use two-dimensional line drawings in patent copywriting.