Inline – The Circuit reverses and remands the construction of claims directed to tamper-resistant plastic food containers having a frangible section that will reveal whether the container has previously been opened. The accused EasyPak frangible section has a single score line along which the cover is severed from the base, whereas the ‘003 patent’s preferred embodiment has two score lines. The district court construed “frangible section” to mean “a removable tear strip, delimited by at least two severable score lines.” The specification described the possibility of one score line, and claim differentiation applies because dependent claims recited the presence of two score lines. Moreover, there is no support for EasyPak’s argument and the district court’s holding that the prosecution history limits the construction to at least two score lines.

Inline Plastics Corp. v. Easypak, LLC., Fed. Cir. Case 2014-1305 (August 27, 2015)

Inline Plastics sued EasyPak for infringement of patents directed to tamper-resistant plastic food containers. Following claim construction, the district court entered final judgment of non-infringement of the ‘003 patent, dismissed without prejudice EasyPak’s declaratory judgment counterclaims for invalidity, and dismissed Inline’s count for infringement of the ‘680 patent with prejudice. Inline appeals the construction of “frangible section” and “tamper evident bridge.” The panel affirms the construction of “tamper evident bridge” in a very brief discussion so this summary will focus on the reversal of the construction of “frangible section.”

The patented containers have a hinged plastic bridge between the top and bottom portions of the container, the bridge having a frangible section that must be severed in order to open the container. The parties agree that claims 1 and 2 are representative:

1. A tamper-resistant/evident container comprising:

a) a plastic, transparent cover portion including an outwardly extending peripheral flange;

b) a base portion including an upper peripheral edge forming at least in part an upwardly projecting bead extending substantially about the perimeter of the base portion and configured to render the outwardly extending flange of the cover portion relatively inaccessible when the container is closed; and

c) a tamper evident bridge connecting the cover portion to the base portion.

2. A tamper-resistant/evident container as recited in claim 1, wherein the tamper evident bridge includes a hinge joining the outwardly extending flange of the cover portion with the base portion, the hinge including a frangible section, which upon severing, provides a projection that extends out beyond the upwardly projecting bead of the upper peripheral edge of the base portion, for facilitating removal of the cover portion from the base portion to open the container.

The district court acknowledged that it limited the claims to the embodiment shown in Figure 1, and stated that “declarations made during patent prosecution to surpass the prior art reveal a definitive focus on the removability of the frangible section and thus clearly and unambiguously disavow any other embodiment to the contrary.”

The Specification Discloses an Alternate Embodiment with One Score Line

The specification describes the preferred embodiment as:

Preferably, frangible strip 18 is limited at least in part by a pair of parallel score lines 42a, 42b or areas that have been weakened or stressed during the forming process.

The specification also states that a single score line or perforation is an alternative embodiment:

Alternatively, the integral hinge 16 could be formed with a single score line or perforation line, rather than a pair of score lines. In this instance, the single score line could be severed to create a pair of projections which would be used to open the container.

Despite this explicit disclosure of an alternative single score line, the district court limited “frangible section” to require at least two score lines, referring to the frequency with which the specification described the frangible section as having two score lines that form a severable strip.

The Prosecution History Does Not Limit Coverage to At Least Two Score Lines

EasyPak states that the prosecution history supports construction of “frangible section” to require at least two score lines. During prosecution, the examiner initially rejected claims 1 and 2 as anticipated by either Urciuoli or Menshen, and rejections on the ground of obviousness were based on these references and also in view of Terauds. In response, Inline emphasized that no reference showed a frangible section which, upon severing, “provides a projection that extends out beyond the upwardly projecting bead of the upper peripheral edge of the base portion for facilitating removal of the cover portion from the base portion to open the container.” Inline described Urciuoli’s frangible section as “a perforated line, a groove or the like around the receptacle in the outer segment.”

EasyPak states that Inline distinguished its invention from Urciuoli on the basis that Urciuoli’s frangible section features a single perforated line. We cannot find such a statement in either the reference or the prosecution history. Inline’s description of Uricuoli as containing a “perforated line, a groove or the like,” was not the basis of Inline’s distinction.

EasyPak also argues that the declarations that Inline submitted to the PTO limit the claims to a tear strip having two score lines. The declarations described Inline’s commercially successful containers as having a frangible hinge with a removable tear strip. His statements describe the commercial embodiments and focused on the long-felt need met by Inline’s commercial products. However, he did not address the number of score lines in the frangible section, and did not focus on the scope of the claims.

In allowing the claims, the patent examiner placed no emphasis on the number of severable lines, explaining: “The container also includes a tamper evident feature, such as a tear strip, connecting the cover portion to the base portion.” There is no discussion in the specification or the prosecution history of any patentability reliance on the number of score lines by which the frangible section is severed.

Claim Differentiation Supports the Broader Construction

Contrary to the district court’s ruling, claim differentiation clearly supports a construction of claim 1 that would cover “at least one score line or at least one perforation line.”

Claim 4 depends from claim 2 and is specific to the embodiment of two parallel score lines:

4. A tamper-resistant/evident container as recited in claim 2, wherein the frangible section of the hinge is delimited at least in part by a pair of parallel score lines.

Thus we correct the district court’s claim construction, and construe “frangible section” to mean “a section of material that includes at least one score line or at least one perforation line.”