CAFC reverses US District Court for the Southern District of California on Claim Construction and Satisfaction of Written Description Requirement

In THE LARYNGEAL MASK COMPANY LTD. AND LMA NORTH AMERICA, INC., v. AMBU A/S, AMBU INC., AND AMBU LTD, 10-1028 (CAFC, September 21, 2010), the CAFC reversed the US District Court for the Southern District of California on Claim Construction and Satisfaction of Written Description Requirement. The Laryngeal Mask Company Ltd. and LMA North America, Inc. (collectively, LMA) appealed the district court's summary judgment that the Aura40™, AuraOnce ™, and AuraStraight™ products made by Ambu A/S, Ambu Inc., and Ambu Ltd. (collectively, Ambu) did not infringe the asserted claims of U.S. Patent No. 7,156,100 ('100 patent) and that all claims were invalid for lack of written description under 35 U.S.C. Section 112. Laryngeal mask airway devices were pioneered in the 1980s by Dr. Archibald Brain, the inventor listed on the '100 patent. According to the '100 patent, one problem with prior art laryngeal mask airway devices is that during insertion, the leading edge of the deflated cuff will occasionally fold over on itself, allowing the more rigid end of the mask to catch the inside of the patient's throat. This can be unpleasant for the patient and may prevent the cuff from making a full seal around the patient's laryngeal inlet.

The invention of the '100 patent seeks to minimize the risk that the deflated cuff will fold over on itself by adding a reinforcing rib which serves to stiffen the leading end of the LMA-device during the course of the procedure for its insertion.

The district court construed the disputed terms of the '100 patent. Relevant to this appeal, the court construed the claim term "backplate" as "the relatively rigid mask structure surrounded by the cuff and including a tube joint."

The tube joint is the connection between the mask and the airway tube. See, e.g. , '100 patent figs. 2-3. The district court concluded that Ambu's accused devices did not have a tube joint because the mask structure and the airway tube are integral y molded. They are one continuous piece rather than two pieces joined together by a joint. Because the accused products lacked a tube joint the district court concluded they lacked a backplate.

Therefore, the court granted summary judgment that Ambu's Aura40, AuraOnce, and AuraStraight products did not literal y infringe claims 1 to 6 of the '100 patent.

The district court further granted Ambu's motion for summary judgment of invalidity for lack of written description.

The court determined that the specification failed to adequately describe a mask having at least a portion of the posterior portion of a wall of the cuff in the distal region being thicker and stiffer than other portions of the cuff, as required by claim 1. Id. at 4-6. The court thus concluded that claim 1 and its dependent claims were invalid under 35 U.S.C. Section 112,

Ambu argued that the claim limitation "back-plate" should be construed to include a tube joint.

The CAFC stated that "Although it is a close case, in light of the claim language, specification, and prosecution history, we conclude that the term backplate is not so limited. The claims themselves are limited to the mask structure. The claims require "a backplate" defining a passage."

Although there is ample discussion of the tube joint throughout the specification, there is only one place where the specification indicates that the tube joint is part of the backplate (in the preferred embodiment's description of Figures 5 and 6): The backplate 52 has a one-piece, integral spoon-shape including a bowl 90 and an external tube-joint 92 oriented proximal y relative to the bowl, as shown in FIGS. 5 and 6.

[T]he claim term will not receive its ordinary meaning if the patentee acted as his own lexicographer and clearly set forth a definition of the disputed claim term in either the specification or prosecution history.). The specification does not clearly contain such a special definition.

Although the preferred embodiment includes a backplate that contains a tube joint, the CAFC held that they do not generally limit claims to the preferred embodiment.

The CAFC further found that the specification did not clearly indicate the patentee's intent to give backplate a unique meaning different from its ordinary and customary meaning to one of skill in the art.

The failure to introduce a dictionary definition for the disputed claim term did not preclude a conclusion that there exists a plain meaning to one of skill in the art.

The CAFC found that the term backplate has a somewhat self-descriptive nature. As the prior art patents indicate it is the plate on the back. In light of the claims, specification, prosecution history, and prior art patents, the court concluded that one of skill in the art would understand the claimed backplate to be "the relatively rigid mask structure surrounded by the cuff."

The CAFC then concluded that one of skill in the art would not conclude that the backplate must have a tube joint and that the inventor did not act as his own lexicographer here and clearly require the backplate to have a tube joint.

Regarding the District Court's summary judgment order on lack of an description, the CAFC stated "adequate written description requires that the applicant "convey with reasonable clarity to those skilled in the art that, as of the filing date sought, he or she was in possession of the [claimed] invention."'

The court then concluded that the district court erred in granting summary judgment that the patent was invalid for failing the written description requirement. The Summary of the Invention does not require that the cuff reinforcement be connected to the backplate. Rather, it describes a reinforcement incorporated into the distal end of the cuff.

The Summary of the Invention further states that "[i]n a preferred aspect," the reinforcement extends from the backplate.

The court agreed with LMA that one of ordinary skill in the art could read these disclosures as providing for a cuff reinforcement in the distal region that need not be connected to the backplate. In addition, we agree with LMA that one of ordinary skill in the art could read the Cuff Wall Thickening Passage as disclosing a thickened cuff portion that need not be connected to the backplate.