Inpro II v. T-Mobile (Fed. Cir. 2006, 05–1233).
Inpro accused T-Mobile and RIM of infringement of its patent relating to electronic devices having user-operable input means such as a thumb wheel. (Pat. No. 6,523,079). After claim construction, the parties stipulated to summary judgment of noninfringement.
Inpro’s PDA design includes a thumbwheel controller with a host interface. The “PDA is designed to run independently by its own [CPU] until it is connected to a host computer. Upon connection to the host computer, the host CPU takes control and can access the memory and other functional units of the PDA.
Inpro appealed the construction of the term “host interface.” Interestingly, the specification only discussed the interface as a parallel bus, and actually disparages serial busses.
The appellate panel agreed the defendants that the term’s definition should be limited to parallel bus interfaces:
The description of a serial connection in the discussion of the expansion bus interface, and the lack of any such description in the discussion of the host interface, reinforce the interpretation of the host interface as requiring a parallel bus interface, for that is the only interface described for that purpose.
The real killer for the plaintiff was that the following line from the patent:
A very important feature of the PDA in an aspect of the present invention is a direct parallel bus interface . . .
Because RIM and T-Mobile use serial ports, they can’t infringe the patent, which is construed to require parallel ports.
Patent Drafting Commentary: This case reinforces the trend of intentional obscurity in patent drafting. Based on this case and others, patent drafters would do well to ensure that nothing in the patent document is “important,” “essential,” “required,” or the like. Those terms do help the patent readers better understand your preferred embodiment, but in court they will only limit your claim scope.
Additional views of Judge Newman: Judge Newman wrote the majority opinion, but added a separate addendum on her own. Judge Newman agreed that the court’s construction of “host interface” was dispositive in this case. However, she argued that the court should have construed all three disputed terms.
I believe we have the obligation to review the construction of the three appealed terms, for the interests of the parties and the public, as well as judicial economy, require final disposition of the issues of claim construction that were decided by the district court, and raised on appeal. This panel’s resolution of this infringement action based solely on the construction of “host interface” does not resolve, or render moot, the interpretation of the other disputed terms. . . .
We should review and decide all three of the disputed claim terms that are presented on this appeal, lest our silence leave a cloud of uncertainty on the patent, its scope, and its validity. Our obligation to the system of patent-based innovation requires no less.
Judge Newman’s view appears to be at odds with Judge Mayer’s recent dissent in Old Town Canoe.