Federal Circuit Finds Prosecution History Does Not Limit Claim Scope Where One Skilled In The Art Would Recognize Statement Is In Error

In Elbex Video, Ltd., v. Sensormatic Electronics Corporation, 2007-1097 (Fed. Cir. November 28, 2007), Elbex owns US Patent No. 4,989,085 (the ‘085 patent).  The ‘085 patent is drawn to a closed circuit television system including a supervisory station from which television cameras are controllable.  The supervisory station includes a video monitor to receive and display signals from the cameras, a device to control the cameras, and a switching device to select one of the cameras to be controlled.  To prevent manipulation of the wrong camera from the supervisory station, the ‘085 patent employs an addressing scheme in which each camera generates a unique first code signal.  The first code signal is sent from the camera with video data to a receiving device of the supervisory station.  A receiving device receives the first code signal, which is then input to a controlling means that generates a second code signal corresponding to the received first code signal and transmits that second code signal with control commands to the camera from which the first code signal was received. 

At issue is claim 1 of the ‘085 patent that recites, in pertinent parts, a “receiving means for receiving said video signals and said 1st code signals;” “said controlling means including control and code generator means for generating control signals to control said television camera and 2nd code signals corresponding to the 1st code signals received in said receiving means and for transmitting said control signals and said 2nd code signals to said televisions camera;” and “operating said television camera in accordance with said control signals when said 2nd code signals coincide with a code allotted to said television camera.”  Elbex sued Sensormatic claiming Sensormatic’s closed circuit television system infringed claim 1 of the ‘085 patent.

The District Court found, on summary judgment, noninfringement as a matter of law in that Sensormatic’s system did not satisfy the addressing limitations of the ‘085 patent.  Specifically, the District Court found that the Sensormatic system relies on addresses for corresponding cameras that are generated by the controller itself according to the number of the video input to which the camera is connected.  As such, the Sensormatic system lacked the second code signal that corresponds to the first code signal as required by the ‘085 patent. 

Further, the District Court found that the claim limitation of “receiving means for receiving said video signals and said first code signals” had been limited during prosecution by the inventor such that “receiving means” only included a “monitor” that receives the video and the first code signal.  Implicit in the District Court’s ruling is that the prosecution statements would not have been viewed by one of ordinary skill in the art to be obvious error. Because of such limitation, the District Court found that the Sensormatic system did not infringe the ‘085 patent since no address signal corresponding to the first code signal is ever sent from the camera to the monitor.

Elbex appealed the grant of summary judgment in favor of Sensormatic.  On appeal, the Federal Circuit disagreed with the District Court regarding the construction of the “receiving means.”  Specifically, relying on Superguide Corp. v. DirectTV Enters. Inc., 358 F.3d 870, 874 (Fed. Cir. 2004) and Omega Eng’g, Inc. v. Raytek Corp., 334 F.3d 1314, 1323 (Fed. Cir. 2003), the Federal Circuit found that “[c]laim terms are entitled to a ‘heavy presumption’ that they carry their ordinary and customary meaning to those skilled in the art in light of the claim term’s usage in the patent specification.”  Slip opinion at 7.  However, such ordinary and customary meaning may not apply when an applicant for patent has surrendered claim scope during prosecution of the application.  In order for such prosecution disclaimer to be effective, the disavowal of claim scope “must ‘be both clear and unmistakable’ to one of ordinary skill in the art.” Id. at 8 quoting Omega Eng’g, Inc., 334 F.3d at 1326.  Further, such disclaimer must be factually accurate in light of the remainder of the prosecution history such that a reasonable competitor would have no reason to believe that a mistake had been made.  Id

The District Court relied on the following statements to find prosecution disclaimer:

To ensure a no-error operation the camera generates a code signal, which is received by the monitor, based upon which, a code is sent back to the camera along with the control signal. Only coincidence of the original camera code and the code returned to the camera will allow the control signals to operate the camera. The principle of the present invention is, therefore a transmission of a code from the camera to the monitor of the receiving means and back to the cameraId. at 4.

The Federal Circuit found that the above statements do not amount to a clear and unmistakable surrender of claim scope.  First, the Federal Circuit determined such statements were not supported by the specification in that nothing in the specification suggests that the monitor of the receiving means receives the first code signal and returns a corresponding code to the cameras.  Second, although the above statements alone may arguably be construed as a disclaimer, when the prosecution history is considered as a whole, such statements are ambiguous.  Third, the above statements, if taken literally, would result in an inoperable system as a “monitor” would not have the hardware necessary to receive and generate a second code signal corresponding to the first signal.  Further, even if the “monitor” did include such hardware, the signal would be blocked by a low-pass filter disposed between the “monitor” and the cameras.  Therefore, one of ordinary skill in the art would understand claim 1 to include a receiving means not limited to a monitor.  Id. at 11.

Because of the misconstruction of the receiving means limitation, the Federal Circuit concluded that the district court erred in granting summary judgment of noninfringement to Sensormatic based on the monitors in the Sensormatic systems not receiving a first code signal. Id.  The Federal Circuit continued on to analyze different Sensormatic systems and arguments of counsel.  The Federal Circuit agreed with the District Court’s grant of summary judgment with respect to two Sensormatic systems but found that summary judgment was improper with respect to one Sensormatic system.  Thus, the Federal Circuit affirmed in part, reversed in part, and remanded for further consideration.  Id. at 15.


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