You may be called upon to determine the strength of patent claims in many circumstances. Perhaps you have been accused of infringing a patent. You may be considering purchasing one. You might want to file a lawsuit asserting the claims of a patent against another and need to know if those claims are at risk of invalidity. When analyzing of the strength of patent claims, you will need to ask a number of questions, including what technology existed at the time the patent application was filed and whether one of skill in the art would understand how to make and use the invention. One key question will be the scope of the claims. If the claims are broad and cover a wide swath of technology, that may make the patent very valuable. However, broader claims also may open up a patent to a challenge that, among other things, its written description does not support the broader claims.
35 USC §112(a) states that a patent specification shall contain a written description of the invention. This is the statutory basis for the written description invalidity defense that the patent claims asserted are not supported by the specification as it was originally filed. The disclosure can be made in the originally filed specification in any way that would be understood by one of ordinary skill in the art to indicate the inventor possessed the full scope of the invention. This disclosure can be made either through words or figures. The originally filed claims are considered part of the specification for purposes of the written description analysis. Because the focus is on what was originally filed, your written description analysis will need to include a thorough examination of the prosecution history of the patent.