Disavowal of Claim Scope in Techtronic Industries co. v. ITC: Federal Circuit Ties Patent to the Described “Invention” and the Problem being Solved

In an opinion focused on claim construction and disavowal, the Federal Circuit in Techtronic Industries co. v. ITC found that a patent’s repeated discussion and focus on providing a passive infrared detector disavowed any products that lack a passive infrared detector.¹

The patent at issue (U.S. Patent No. 7,161,319, or ‘319 patent) relates to “movable barrier operators” such as “garage door operators or gate operators which includes passive infrared detectors associated with them for detecting the presence of a person or other high temperature object.”² According to the specification, it is “known that garage door operators . . . can include a passive infrared detector associated with the head unit of the garage door operator.”³ “Such units were expensive as the passive infrared detector had to be built into the head unit of the garage door operator.”⁴ “Also, the prior PIR detectors were fragile,” and mounting the head unit to the ceiling can cause damage to the passive infrared detector if the head unit collides with the ceiling. ⁵

Thus, according to the patent, “[w]hat is needed is a passive infrared detector for controlling illumination from a garage door operator which could be quickly and easily retrofitted to existing garage door operators with a minimum of trouble and without voiding the warranty.”⁶ The Summary of the Invention section states that it “is a principal aspect of the present invention to provide a quickly and easily retrofitted passive infrared detector for controlling the illumination of a garage door operator through conventional signaling channels.”⁷ For instance, “FIG. 1 is a perspective view of a garage including a movable barrier operator, specifically a garage door operator, having associated with it a passive infrared detector in a wall control unit and embodying the present invention.”⁸

The “garage door operator 10” “includes a head unit 24 for providing motion to the garage door 16” and a “wall control unit 60 embodying the present invention.”⁹ The wall control unit 60 “communicates over a line 62 with the head unit microcontroller 56 to effect control of a garage door operator motor 70.”¹⁰ “The wall control 60, as may best be seen in FIG. 4, includes a passive infrared sensor 100” that “chang[es] signals from” when “infrared illumination changes at the passive infrared sensor 100.”¹¹

Claim 1 of the patent recites

1. An improved garage door opener comprising:
a motor drive unit for opening and closing a garage door, said motor drive unit having a microcontroller
and a wall console, said wall console having a microcontroller,
said microcontroller of said motor drive unit being connected to the microcontroller of the wall console by means of a digital bus.

The patentee filed a complaint at the ITC (the “Commission”), asserting that the respondents (which later became the appellant for this opinion) imported and sold garage door openers which infringed claim 1 of the ‘319 patent.¹² The Commission agreed that the accused products infringe the ‘319 patent. Part of its conclusion was based on a claim construction which does not require the term “wall console” to have a passive infrared detector.¹³ Although the administrative law judge (“ALJ”) in the investigation had found that the patent disavowed wall consoles lacking a passive infrared detector, the Commission found that the record was not sufficiently clear to support a finding of disavowal.¹⁴ In particular, the Commission found that the specification is not sufficiently clear to support a finding of disavowal, because it describes other inventions, such as using digital signal processing techniques to program a microcontroller in the wall console, and found that the prosecution history does not support disavowal, because a related patent includes a claim which expressly recites a passive infrared detector being located in a wall console. The Commission reasoned that the lack of such an express recitation of the passive infrared detector in claim 1 of the ‘319 patent therefore weighs against disavowal.¹⁵

The Federal Circuit (in an opinion by Judge Lourie) reversed the Commission’s claim construction, and concluded that the “the ‘319 patent disavows coverage of wall consoles lacking a passive infrared detector.”¹⁶ The court relied on the patent’s focus on infrared detectors, and pointed out that “the specification, in each of its sections, discloses as the invention a garage door opener improved by moving the passive infrared detector from the head unit to the wall console.”¹⁷ More particularly, the court cited the background section, which states that “locating the [passive infrared] detector in the head unit was expensive, complicated, and unreliable.”¹⁸ According to the court, the “remaining sections of the patent—even the abstract—disclose a straightforward solution: moving the detector to the wall console.”¹⁹ The court further pointed to the discussion of the passive infrared detector in the Abstract, in the Summary of the Invention, in the Brief Description of the Drawings, and in passages of the Detailed Description of the Preferred Embodiments.²⁰ Each of those passages involved the operation of the passive infrared detector.

Although the specification does not expressly disparage wall consoles which lack a passive infrared detector, the Federal Circuit stated that such disparaging statements were not necessary for a finding of disavowal.²¹ Although “mere criticism of a particular embodiment will not always rise to the level of disavowal,” the court appeared to reason that the lack of criticism also does not prevent a finding of disavowal.²² It stated that “the specification plainly represents the scope of the invention to the exclusion of some embodiments,” and that an express statement regarding the impossibility or infeasibility of omitting a passive infrared detector was not necessary, nor was an “express concession” that alternatives to a passive infrared detector were being disavowed.²³

Although the patentee argued that the specification also discusses other inventive aspects, such as using digital signaling techniques to program a microcontroller in the wall console, and that the prosecution history does not support a finding of disavowal, the court did not find those arguments to be persuasive. In particular, it stated that “there is no requirement that the prosecution history reiterate the specification’s disavowal.”²⁴ Although the court found that the prosecution history sheds little on the meaning of the term “wall console,” it also did not contradict the disavowal made in the specification.²⁵ Further, the disavowal overrode any application of the doctrine of claim differentiation, which arises from the lack of an express recitation of the passive infrared detector in the claims at issue, and the presence of such a recitation in a related patent. The court stated that “the fact that [the patentee] obtained more modest claims in its parent patent does not inoculate it from the specification’s disavowal,” and that the doctrine of claim differentiation “will be overcome by a contrary construction dictated by the written description or prosecution history.”²⁶ Lastly, while the court acknowledged that the specification also mentions using a digital signaling technique to program a microcontroller, “the entire purpose of this part of the description is to enable placement of the detector in the wall console.”²⁷ Thus, the Federal Circuit found that the claim term at issue requires a passive infrared detector, and also concluded that this claim interpretation mandated a reversal of the determination of infringement.²⁸

While this opinion illustrates a situation that can lead to disavowal of claim coverage, it also indicates ways in which patent drafters can help their clients preserve claim coverage. More particularly, an important factor that led to the requirement of a passive infrared detector in this case was the specification’s focus on overcoming problems in the prior art with providing an infrared detector for controlling garage door openers, and on the focus on addressing such problems by placing the passive infrared detector in a wall-mounted unit. While it is in principle improper to import limitations from the specification into the claims, the discussion of the problems being addressed by a patent, the presentation of solutions, their alternatives or optional modifications can all have a bearing on the interpretation of the patent claims, because those claims must still be construed in light of the specification. Thus, patent drafters can maximize the claim coverage for their clients by engaging the inventors to explore not only specific solutions for which patent coverage is being sought, but also to explore what are the optional modifications and alternatives that can be described in the patent specification.