Berall v. Teleflex Medical — Federal Circuit Holds “Mounted On” Means Exterior Attachment, Affirms Noninfringement of Laryngoscope Patent

Background

Dr. Jonathan Berall, an emergency medicine physician, holds U.S. Patent No. 5,827,178, which covers a video laryngoscope — a device used to visualize the airway during tracheal intubation. The key feature of the invention is a camera mounted on the distal end of the laryngoscope blade, connected to a display screen that allows the medical professional to see the airway in real time without repositioning their head.

Dr. Berall originally sued LMA North America in the Southern District of New York in 2010, asserting that LMA’s McGrath Series 5 video laryngoscope infringed claims 1–15 of the ‘178 patent. The case was stayed for eight years while the Patent Office conducted reexamination — ultimately confirming all asserted claims in 2019. By then, LMA had been acquired by Teleflex, which assumed the defense. After Dr. Berall filed a Second Amended Complaint adding Airtraq laryngoscopes as accused products and naming Teleflex as a defendant in its own right, the Southern District of New York transferred the case to the Eastern District of North Carolina, where Teleflex is headquartered.

The critical dispute turned on claim construction: does “camera means mounted on the blade” require external (exterior) attachment, or does it include a camera housed inside the blade with only its lens exposed? The Eastern District construed “mounted on” to mean “fastened to the exterior of,” then granted Teleflex summary judgment because the McGrath Series 5 camera sits inside a protective CameraStick housing — its lens is merely exposed to the outside, not fastened externally. Dr. Berall appealed.

The Court’s Holding

The Federal Circuit unanimously affirmed on all three issues before it.

Claim construction — “mounted on” means exterior attachment. Writing for the court, Judge Stoll held that the contrast between “mounted on” and “mounted in” within the same patent creates a strong inference that the patentee intended different meanings. Claim 1 uses “camera means mounted on the blade” and claim 5 uses “a screen mounted on the handle” — both referring to components that the specification consistently depicts as externally attached. Claim 4, by contrast, uses “power supply means are mounted in the handle” — referring to a component the specification shows housed within the handle. This parallel structure, the court explained, supports reading “mounted on” to mean something qualitatively different from (and narrower than) “mounted in” — namely, exterior attachment.

Noninfringement — literal and doctrine of equivalents. Because the court adopted the district court’s construction, literal noninfringement followed: the McGrath Series 5 camera is fastened inside the CameraStick, not to the exterior of the blade. On doctrine of equivalents, the court affirmed summary judgment for two reasons. First, Dr. Berall’s insubstantial-differences argument failed to address the claim on a limitation-by-limitation basis — the circuits require “particularized testimony and linking argument” for each limitation separately, not a general assertion. Second, Dr. Berall had presented his function-way-result analysis only in an expert report incorporated by reference, not in his summary judgment briefing, which the district court properly struck as a violation of its local rules.

Venue — no waiver by Rule 25(c) successor. Dr. Berall argued Teleflex waived its venue objection when it answered the First Amended Complaint on LMA’s behalf. The court disagreed, relying on Federal Rule of Civil Procedure 25(c): when a successor-in-interest steps into litigation, it litigates “in the shoes” of the original party and does not thereby subject itself to venue objections for claims that name it as a separate defendant. Only when Dr. Berall added independent claims against Teleflex in his Second Amended Complaint did Teleflex’s own venue rights come into play — and Teleflex timely asserted them.

Key Takeaways

• Preposition contrast is powerful claim construction evidence. Using “mounted on” and “mounted in” in the same patent — for components the specification consistently depicts as external vs. internal — creates a strong, nearly dispositive inference that the two phrases carry different spatial meanings. Patentees should be precise and consistent with spatial prepositions across claims and drawings.
• Doctrine of equivalents requires limitation-specific evidence at summary judgment. A high-level expert opinion that the accused product is “insubstantially different” from the claimed invention is not enough. Each limitation must be separately analyzed with particularized testimony; incorporating an expert report by reference without independent argument in summary judgment briefs can forfeit the argument entirely.
• Rule 25(c) successors-in-interest do not waive venue for separately asserted claims. A defendant who steps into litigation as a successor does not voluntarily submit to venue as to claims later raised against it in its independent capacity. Plaintiffs who add a corporate successor as a separate defendant open a fresh window for venue challenges.

Why It Matters

Berall v. Teleflex is a reminder that small preposition choices in patent claims — “on” vs. “in” vs. “to” — can make or break a case. Courts read the entire claim set as a coherent whole, so if a patentee uses two different spatial terms in the same document, courts will presume they mean different things. For medical device and hardware inventors, the lesson is to draft figures and claim language consistently: if a component is interior in every figure, describing it as “mounted on” the housing risks a narrowing construction that excludes exactly the kind of shielded cameras used in modern laryngoscopes.

The doctrine of equivalents holding reinforces a recurring Federal Circuit theme: equivalents arguments require rigorous, limitation-by-limitation expert support. Litigants who save their theory for an expert report — hoping to incorporate it by reference at summary judgment — face an uphill battle. And the venue ruling provides a practical roadmap for defendants acquired mid-litigation: each time a complaint is amended to name the successor as a distinct defendant, the successor’s venue clock resets.