Authorities Cited: United States Patent and Trademark Office U.S. Patent No. 4,048,746 U.S. Patent No. 4,200,809 U.S. Patent No. 5,269,091 U.S. Patent No. 5,949,636 Supreme Court 383 U.S. 1, 36 Circuit Courts 749 F.2d 707, 719 927 F.2d 1552, 1557 4 F.3d 1153, 1166 275 F.3d 1347, 1353 311 F.3d 565, 568 363 F.3d 1219, 1223 485 F.3d 1157, 1162 Federal Rules of Civil Procedure Fed. R. Civ. P. 50(a)