"Software may be patent eligible, but when a claim is not directed towards a process, the subject matter must exist in tangible form."  This was part of the Federal Circuit's recent holding in Allvoice Developments US, LLC v. Microsoft Corp, affirming a district court's invalidation of claims 60-68 of Allvoice's U.S. Patent No. 5,799,273 ("the '273 Patent") for not being directed to one of the four statutory categories of inventions identified in 35 U.S.C. § 101 (machines, processes, articles of manufacture, and compositions of matter).  In affirming the district court, the Federal Circuit noted that although software is not per se patent-ineligible, the claims in question were invalid because they were not directed to a process and were limited to software instructions without any hardware limitations.  The Federal Circuit also affirmed the district court's decision concluding that Microsoft's accused products did not infringe the '273 Patent.

Claim 60 of the '273 Patent, exemplary of the claims at issue, recites:

60.  A universal speech-recognition interface that enables operative coupling of a speech-recognition engine to at least any one of a plurality of different computer-related applications, the universal speech-recognition interface comprising:

            input means for receiving speech-recognition data including recognised words;

            output means for outputting the recognised words into at least any one of the plurality of different computer-related applications to allow processing of the recognised words as input text; and

            audio playback means for playing audio data associated with the recognised words.  

('273 Patent, col. 29 lines 22-34).

In analyzing the claims, the Federal Circuit concluded that, despite reciting a "speech-recognition interface," claims 60-68 did not recite a process or any tangible or physical object and, thus, did not fall within any of the categories of eligible subject matter.  Citing Digitech Image Techs., LLC v. Elecs. for Imaging, Inc., the Federal Circuit explained that "[e]xcept for process claims, 'the eligible subject matter must exist in some physical or tangible form.'"  Slip op. at 14.  In particular, a machine must be "a concrete thing, consisting of parts, or of certain devices and combination of devices;" a manufacture must be "a tangible article that is given a new form, quality, property, or combination through man-made or artificial means;" and a composition of matter "requires the combination of two or more substances and includes all composite articles."  Slip op. at 14-15. 

With respect to the physical nature of the claimed subject matter, Allvoice argued that the claimed interfaces are "software instructions" and that "the claimed software must necessarily be in a machine readable, physical state, in order to exist." (emphasis added).  Slip op. at 16.  Therefore, Allvoice contended, "the district court...should have concluded that these claims are directed to a manufacture, one of the four categories of patentable inventions."  Slip op. at 16.  However, the Court observed that while "[s]oftware may be patent eligible, . . .  when a claim is not directed towards a process, the subject matter must exist in tangible form."  Slip op. at 16.  Additionally, the Court declined "to import or, as Allvoice argued, 'imply' a tangible medium into claims that fail to recite or reference any such medium." Slip op. at 17.

Because the claimed subject matter was not directed to a tangible article and because the claims were not directed to a process, the Federal Circuit concluded that the claims fell outside of allowable subject matter as defined by 35 U.S.C. § 101.

While this decision does not appear to break any new ground, the Federal Circuit has provided some guidance for claiming software-related inventions.  In view of the decision, one is forced to wonder if the outcome might have been different if the means of claim 60 had been more clearly tied to the physical structures of the computer system that appears in Figs. 1 and 2 of the '273 Patent.  Regardless, while software claims directed to a process do not necessarily have to recite hardware to be patent-eligible, the lesson to be learned (or "re-learned") is to explicitly recite a tangible medium in non-method software claims, especially since the Federal Circuit has declined to import or imply a tangible medium into software product claims that fail to recite or reference any such medium.