Software patent applications present pitfalls not present for other inventions, because software is intangible. To pass muster in the USPTO, software is best described as a process, one of the four categories of patent eligible subject matter under USC 35 § 101. The other three are machine, manufacture and composition of matter. Some software patent applications have been prosecuted—and some patents granted—claiming software not as a process but as a product or part of a system.

A recent case from the Patent Trial and Appeal Board (PTAB), Ex parte Doyle, illustrates the lines drawn by patent examiners when software is described and claimed in the application as a “computer program product,” with these elements:

  • computer readable storage medium
  • a computer readable program code having specific capabilities

This was stated as existing as “an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.).” It was also described as taking “the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon.” The PTAB found that the application failed to exclude transitory signal as part of the invention, and so ran afoul of Ex parte Nuijten, a 2007 Federal Circuit case. The PTAB also cited one of its own precedential opinions, Ex parte Mewherter, which held that the specification – or the claims – should be written to exclude transitory electrical signals from the invention. As expressed in Nuijten, a “signal” does not fit within one of the four statutory classes of subject matter. As a practice tip from Mewherter, if software is claimed as a “product” instead of a “process,” then the claims must be written to include only “non-transitory” components. Another practice tip from Mewherter: Labeling the components merely “physical” or “tangible” is not good enough to overcome a presumption “that those of ordinary skill in the art would understand the claim term ‘machine-readable storage medium’ would include signals per se.”