Source: http://www.kinney.com/blog/2015/11/01/means-or-not-means-that-is-the-question/
Timestamp: 2019-04-21 00:50:35+00:00

Document:
The presence or absence of the word “means” in a claim has long been accompanied by one of two comp-lementary presumptions. Using the word “means” in a claim element creates a rebuttable presumption that §112, para. 6 applies and means-plus-function claiming occurs. Conversely, failure to use the word ‘means’ also creates a rebuttable presumption — this time that §112, para. 6 does not apply. Since 2004, however, these presumptions have been asymmetric ones. The Federal Circuit first established this asymmetry with the Lighting World, Inc. v. Birchwood Lighting, Inc., 382 F.3d 1354, 1358 (Fed. Cir. 2004) decision, which established that “the presumption flowing from the absence of the term ‘means’ is a strong one that is not readily overcome.” (Emphasis added).
To overcome the presumption that a “means”-less limitation is not a means-plus-function element, either: i) the claim term must fail to recite sufficiently definite structure; or ii) the claim term must recite function without reciting sufficient structure for performing that function.
i) Does the claim term recite sufficient definite structure?
ii) Does the claim term recite function without reciting sufficient structure for performing that function?
Although the court conceded that portions of the disputed limitation do describe certain inputs and outputs at a very high level (e.g., communications between the presenter and the audience member computer systems), the claim does not describe how such the recited functions operate “in a way that might inform the structural character of the limitation-in-question or otherwise impart structure.” Williamson attempted to rescue the sought-for structure by pointing to figures of the specification. But the only figures provided therein were exemplary display interfaces and were not considered disclosures of the algorithm corresponding to the claimed function.
First takeaway: There is now a heightened risk when claiming elements functionally, that a future court may construe the claims according to §112(f), formerly §112, para. 6. Simply omitting the word “means” may not be enough to avoid a §112(f) construction.
In addition to the two above articulated reasons that structure must be disclosed, disclosed structure is also required: iii) to rescue a non-§112(f) limitation from a §112(a) rejection which would automatically attach to non-§112(f) limitations that are purely functional.

References: §112
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