Mercedes Successful Invalidating Driver Sleepiness Detection Patent

USPat6313749_Fig1The case of Ibormeith IP LLC v. Mercedes-Benz USA, LLC, Dkt. No. 2013-1007 (Fed. Cir. Oct. 22, 2013) is another case where means-plus-function claims were found invalid for lack of an adequate algorithm/structure disclosed in the description of the patent.

Ibormeith sued Mercedes alleging that Mercedes vehicles having an Attention Assist feature infringed U.S. Patent No. 6,313,749. The ‘749 patent is titled, “Sleepiness Detection for Vehicle Driver or Machine Operator.” The ‘749 patent is directed to monitoring conditions affecting or behavior reflecting a vehicle driver’s sleepiness. Then issuing a warning to the driver before driving is unduly impaired.

Sleepiness Warning
The patent discloses monitoring that takes into account sleepiness factors including, as summarized by the court, “natural body-clock (circadian rhythm), the magnitude and number of corrective steering action the driver is taking, the cabin temperature, the monotony of the road, and how long the driver has been driving.” The factors are “individually weighed, according to contributory importance, and combined in a computational decision algorithm or model, to provide a warning indication of sleepiness.”

Means Claims Language
Claim 1 provided this means clause: “…computational means for weighting the operational model according to time of day in relation to the driver or operator circadian rhythm pattern(s) and for deriving, from the weighted model, driver or operator sleepiness condition and producing an output determined thereby…” Claim 9 provided this means clause: “…computational means for computing steering transitions and weighing that computation according to time of day, to provide a warning indication of driver sleepiness…”

Lack of Structure In Specification
The court recited the rule for means-plus-function clauses: “For a claim to be definite, a recited algorithm, or other type of structure for a section 112(f) claim limitation, need not be so particularized as to eliminate the need for any implementation choices by a skilled artisan; but it must be sufficiently defined to render the bounds of the claim—declared by section 112(f) to cover the particular structure and its equivalents—understandable by the implementer.”

However the Federal Circuit found that these means clauses if the ‘749 were not tied to a structure or defined with sufficient particularity in the specification. As a result the requirements of 35 USC 112, sixth paragraph were not complied with and the claims were held invalid.

The specification provided a formula in table 10 that provided “sleep propensity algorithm – definition “S mod = S circ + S zerox + S rms + S light + S temp + S sleep + S road + Strip.” However, Ibormeith’s expert provided that the algorithm was not based on a simple adding of already weighted inputs. This approach was likely taken to insure that the claims were interpreted broadly enough to cover Mercedes vehicles.

The court recognized that under Ibormeith’s interpretation a person of ordinary skill in the art would need to devise his or her own method for determining driver drowsiness based on the factors. The court concluded that “[a] description of an algorithm that places no limitations on how values are calculated, combined, or weighted is insufficient to make the bounds of the claim understandable.”

Drafting Tips: Provide at Least one Non-Means-Plus-Function Claim Set
This is another in a string of cases where the court has found that means-plus-function claims are invalid in technology related patents where the description fails to provide a sufficiently detailed explanation of the algorithm/structure corresponding to the means clause in the patent. It is better to avoid means-plus-function based claim limitations in at least one claim set, if any. Drafting at least one claim or claim set not including a 112(f) or 112, sixth paragraph claim avoids indefiniteness problems associated with means-plus-function claiming.

Sufficient Computer Structure Disclosure for Means-Plus-Function Elements

HTC Corp v. IPCom GMBH, Dkt. No. 2011-1004 (Fed. Cir. Jan 30, 2012) [PDF].

HTC sue IPcom for declaratory judgement of non-infringement of IPCom’s Patents, including U.S. Pat. No. 6,879,830 and IPCom countersued for infringement. The ‘830 patent is directed to the handover of a cellular phone from one base (tower) to another, as for example, when a person uses a cell phone in a car traveling between coverage areas.  The invention is intended to reduce the chance of service interruption during the handover.

Claim 1 provides:

A mobile station for use with a network including a first base station and a second base station that achieves a handover from the first base station to the second base station by:

storing link data for a link in a first base station,

holding in reserve for the link resources of the first base station, and

when the link is to be handed over to the sec-ond base station:

initially maintaining a storage of the link data in the first base station,

initially causing the resources of the first base station to remain held in reserve, and

at a later timepoint determined by a fixed pe-riod of time predefined at a beginning of the handover, deleting the link data from the first base station and freeing up the resources of the first base station, the mobile station comprising:

an arrangement for reactivating the link with the first base station if the handover is unsuc-cessful.

At summary judgement, HTC claimed that claims 1 and 18 (similar to claim 1), were invalid as indefinite because (1) they claimed both an apparatus and method steps and (2) the patent failed to disclose structure corresponding to the claimed means-plus-function element “arrangement for reactivating.”

Over Emphasis on Prosecution History. While the district court found the claims invalid because they claimed both apparatus and method steps, the Federal Circuit disagreed.  The Federal Circuit found the claim was an apparatus claim directed to a moble station (cellular phone) to be used within a network. In interpreting the claim language the Federal Circuit considered factors set out in Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc): (1) the words of the claim, (2) the specification, (3) the prosecution history, and (4) extrinsic evidence. The Federal Circuit found that the district court put too much emphasis on the prosecution history. The patentee in response to an office action stated, “the cited section of [the prior art reference] clearly describes a process that is completely different from the claimed process. . .” (emphasis added). The Federal Circuit  noted that “claim language and the specification generally carry greater weight than the prosecution history.” The court found that the attorney’s signle reference to a “process” in response to an office action was insufficient when viewed in relation to the plain language of the claims and specification.

Sufficient Computer Structure. The Federal Circuit found that the district court erred in finding that the disclosure of a processor and transceiver was sufficient structure. The Federal Circuit noted that when considering whether their is sufficient support in the specification for a means-plus-function limitation, the disclosure of a general purpose computer or micro processor is not enough. Instead an algorithm must also be disclosed which the computer/processor executes. A patent must disclose “a means for achieving a particular outcome, not merely the outcome itself.” Yet, the appellate court found HTC waived any argument regarding whether the ‘830 patent disclosed a sufficient algorithm.

Further, the Federal Circuit rejected HTC’s argument that the specification needed to disclose the precise circuitry, components, or schematics or controllers would be employed. The court provided that level of hardware disclosure is not necessary, stating “as long as a sufficient algorithm describing how a general-purpose computer will perform the function is disclosed, reference to such general-purpose processors will suffice to overcome an indefiniteness challenge.”