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One should understand the basics of how to determine whether an item infringes a design patent.

The Doctrine of Equivalents allows infringement to be found in some cases where the elements of the accused device are substantially equivalent to the corresponding elements of the asserted claim. K-2 Corp. v. Salomon S.A., 191 F.3d 1356, 1366, 52 USPQ2d 1001 (Fed. Cir. 1999). The Doctrine of Equivalents prevents an accused infringer from avoiding infringement by changing only minor or insubstantial details of a claimed invention while retaining the essential functionality of each of those details. Thus, a device that does not literally infringe a claim may nonetheless infringe under the Doctrine of Equivalents if every limitation in the claim is literally or equivalently present in the accused device or method. Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 41 USPQ2d 1865, 1876 (1997). This “all elements” rule of the Doctrine of Equivalents requires that an alleged infringing device have an identical or equivalent element for each limitation contained in the claim of the alleged infringed patent. Loral Fairchild Corp. v. Sony Corp., 50 USPQ2d 1865, 181 F.3d 1313, 1327.