On the existing technology in patent law

Yes, as long as the technology that the public can know is the existing technology, whether you apply for a patent or not. If it is internal material, it can't be known to outsiders. Yes, as long as the technology that the public can know is the existing technology, whether you apply for a patent or not. If it is internal material, what cannot be known to outsiders is not considered as prior art. The answer to the question you said is correct. The patent invalidation shall be declared by the Patent Reexamination Board. This is not prior art.. The answer to your question is correct. The patent invalidation shall be declared by the Patent Reexamination Board.