Claim construction refers to analyzing a set of patent claims in order to determine what they mean.
In making this determination, a court may consider:
-the plain and ordinary meaning of a term;
-what the specification teaches;
-what is described in the prosecution history;
-how the term is used in other claims; and
-in some cases, what experts believe the term means.
A set of rules called "The Canons of Claim Construction" govern how claims should be interpreted. These rules can be found at Patently-O:
http://patentlyo.com/patent/2004/11/the_canons_of_c.html
With respect to expert testimony, courts are generally loathe to rely on this, since the opinions of experts are often colored by hindsight and the interests of litigants who employ them. One court even stated that if a person cannot rely on the intrinsic evidence--i.e., the patent itself and its prosecution history-- then the claims are not properly serving their notice function (Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582-83 (Fed. Cir. 1996)) and denied the use of extrinsic evidence altogether.
In making this determination, a court may consider:
-the plain and ordinary meaning of a term;
-what the specification teaches;
-what is described in the prosecution history;
-how the term is used in other claims; and
-in some cases, what experts believe the term means.
A set of rules called "The Canons of Claim Construction" govern how claims should be interpreted. These rules can be found at Patently-O:
http://patentlyo.com/patent/2004/11/the_canons_of_c.html
With respect to expert testimony, courts are generally loathe to rely on this, since the opinions of experts are often colored by hindsight and the interests of litigants who employ them. One court even stated that if a person cannot rely on the intrinsic evidence--i.e., the patent itself and its prosecution history-- then the claims are not properly serving their notice function (Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582-83 (Fed. Cir. 1996)) and denied the use of extrinsic evidence altogether.