Patent attorneys beware how you respond to restriction requirements because your response may cause patent prosecution estoppel.


In this case, Plantronics filed suit against Aliph and Alipcom (collectively “Aliph”) alleging that Aliph infringed on US Patent No. 5,712,453.

The ‘453 patent is directed to concha-style headsets for transmitting received sounds to the ear of a user. Essentially, the ‘453 patent is directed to headphones (ear buds) that are inserted into a user’s ear that use the concha of the user’s ear to stabilize the headphones. The headphones are stabilized in a user’s ear without projections hooking onto the user’s ear.

During prosecution of the ‘453 patent, the patent examiner at the USPTO issued a restriction requirement stating the ‘453 patent’s claims were directed towards 4 different inventions. Plantronics elected a set of claims associated with FIGURES 1A and 1B of the specification, which resulted in the ‘453 patent. It is of note that the restriction requirement did not state why there were multiple inventions in the species.

During litigation, the district court construed a claimed limitation of “stabilizer support member” as “an elongated structure that extends from the ear cushion to the concha stabilizer pad and stabilizes the headset.” Where in the district court dismissed concha infringement claim, and clarified that the meaning of “elongated” means a structure that is “longer than it is wide.” Plantronics contented that the districts court’s claim construction is improper because the claimed limitation does not a further definition of a stabilizer and a stabilizer is only a structure that simply “Extends from something else.” Aliph on the other hand argued that Plantronics elected a species of the invention that is limited to elongated structure, that the “stabilizer” includes the limitation of an “elongated stabilizer.”

The court of appeals differentiated this case from LG electronics Inc. v. Bizcom Electronics and Acco Brands, Inc. v. Micro Security Devices, Inc. because in both these cases restriction requirements were issued that demarcated the actual differences among the species of the invention. During patent prosecution of the ‘453 patent the patent examiner found four patentably distinct inventions without providing any reasons why these features represented different species. Therefore, the court of apple couldn’t discern or read into why the examiner thought there were four different inventions and the term “elongated” could not be read into the claims. Based on this new claim construction, the court of appeals reversed and remanded the district court’s grant of Alphi’s motion of summary judgment of non-infringement.


  1. When responding to restriction requirements it is important to look at why the patent examiner believes that there are different inventions within a claim set. If the case is merely one where different figures represent different inventions and the examiner only desires to review one grouping of figures, then patent prosecution estoppel may not be formed based on the figures. However, if the examiner gives clear differences between the claim sets, then divisional patent applications may be necessary.
  2. If the examiner clearly demarcates how claim sets include different limitations and are directed towards different inventions, a generic claim that reads on all the species may be beneficial. By filing a response to a restriction requirement with a generic claim it may be possible to claim rejoinder of species with an allowable generic claim. See MPEP 806.06.
  3. This is a great case where the patent attorneys for Plantronics limited their prosecution history while broadly generated claims. It is likely that during prosecution they could have overcome art by defining the specific shape of their headphones, but by broadly reciting claim limitations without regarding the structure of their claims they obtained good claims for their granted patent. This case would have been fairly easy if they had used “means for” limitations in their claims, where the structure would have been those recited in the specification, which may have limited their claims.
  4. When looking at this case and how it may apply to mobile applications/software patents, it is important to not specifically state in your claims the type of processor, client side device, end-user device that is performing a limitation. Instead limitations may be recited that a mere “processor” performs actions without further clarifying what is performing an action. Furthermore, in telecommunications and data processing patent applications it is important to not clarify what data transfer protocols are used unless they are absolutely necessary. This is because standards change rapidly. If your patent application had claims directed to mobile phones communicating data on only a 3g network or using 801.b wifi protocols, these patents would be much less valuable than patents without these limitations.
By | 2013-07-31T19:27:30+00:00 July 31st, 2013|Patent Attorney Takeaways|Comments Off on PLANTRONICS, INC. V. ALIPH, INC. And ALIPHCOM, INC