Authored by: Jeremy J. Gustrowsky
A recent decision involving Google LLC and EcoFactor, Inc. sheds light on how patent claims should be interpreted, especially when it comes to whether listed inputs in a method claim must be completely separate or can be intertwined. The case centered on U.S. Patent No. 8,498,753, which covers smart thermostat technology that optimizes heating and cooling by considering both indoor and outdoor temperatures, as well as other factors. Google challenged the validity of this patent, arguing that prior art already disclosed the claimed invention.
The heart of the dispute was a claim limitation that required determining when to turn on a climate control system based on five different inputs, such as internal and external temperatures and the system’s performance characteristics. The Patent Trial and Appeal Board (PTAB) originally ruled that each of these five inputs had to be entirely distinct—meaning, for example, that you couldn’t use an internal temperature reading to help calculate another required input. This strict interpretation led the Board to reject Google’s argument that the prior art met all the claim requirements.
On appeal, the Federal Circuit disagreed with the Board’s narrow reading. The court explained that unless the patent specifically says otherwise, claim language like “based at least in part on” is broad and flexible. The judges found that the patent’s language and its description did not require each input to be completely separate. In fact, the patent’s own examples showed that some inputs could be calculated using others. The court concluded that the Board’s construction was too restrictive and that the correct interpretation is that each input must be used in the calculation, but they can be related or derived from one another.
This decision is a reminder that patent claims should be read in light of the entire patent and not artificially narrowed unless the patent clearly demands it. For inventors and companies alike, it underscores the importance of clear claim drafting and the potential pitfalls of overly rigid interpretations during patent challenges.