Editing MPEP 2182

<noinclude>{{MPEP Section|2181|2100|2183}}</noinclude>

==[[MPEP 2182|2182 Scope of the Search and Identification of the Prior Art]]==

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As noted in MPEP § 2181, in In re Donaldson Co., 
16 F.3d 1189, 29 USPQ2d 1845 (Fed. Cir. 1994) the 
Federal Circuit recognized that it is important to 
retain the principle that claim language should be 
given its broadest reasonable interpretation. This principle 
is important because it helps insure that the statutory 
presumption of validity attributed to each claim 
of an issued patent is warranted by the search and 
examination conducted by the examiner. It is also 
important from the standpoint that the scope of protection 
afforded by patents issued prior to Donaldsonare not unnecessarily limited by the latest interpretation 
of this statutory provision. Finally, it is important 
from the standpoint of avoiding the necessity for a 
patent specification to become a catalogue of existing 
technology. The specification need not describe the 
equivalents of the structures, material, or acts corresponding 
to the means- (or step-) plus-function claim 
element. See In re Noll, 545 F.2d 141, 149-50, 191 
USPQ 721, 727 (CCPA 1976) (“The meaning of 
‘equivalents’ is well understood in patent law, … and 
an applicant need not describe in his specification the 
full range of equivalents of his invention.”) (citation 
omitted). A patent specification need not teach, and 
preferably omits, what is well known in the art. 
Hybritech Inc. v. Monoclonal Antibodies, Inc., 
802 
F.2d 1367, 1384, 231 USPQ 81, 94 (Fed. Cir. 
1986).

The Donaldson decision thus does not substantially 
alter examining practice and procedure relative to the 
scope of the search. Both before and after Donaldson, 
the application of a prior art reference to a means or 
step plus function limitation requires that the prior art 
element perform the identical function specified in the 
claim. However, if a prior art reference teaches identity 
of function to that specified in a claim, then under 
Donaldson an examiner carries the initial burden of 
proof for showing that the prior art structure or step is 
the same as or equivalent to the structure, material, or 
acts described in the specification which has been 
identified as corresponding to the claimed means or 
step plus function.

The “means or step plus function” limitation should 
be interpreted in a manner consistent with the specification 
disclosure. The Federal Circuit explained the 
two step analysis involved in construing means-plus-
function limitations in Golight Inc. v. Wal-Mart Stores 
Inc., 355 F.3d 1327, 1333-34, 69 USPQ2d 1481, 1486 
(Fed. Cir. 2004): 

The first step in construing a means-plus-function claim 
limitation is to define the particular function of the claim 
limitation. Budde v. Harley-Davidson, Inc., 250 F.3d 
1369, 1376 [58 USPQ2d 1801, 1806] (Fed. Cir. 2001). 
“The court must construe the function of a means-plus-
function limitation to include the limitations contained in 
the claim language, and only those limitations.” Cardiac 
Pacemakers, Inc. v. St. Jude Med., Inc., 296 F.3d 1106, 
1113 [63 USPQ2d 1725, 1730] (Fed. Cir. 2002)…. The 
next step in construing a means-plus-function claim limitation 
is to look to the specification and identify the corresponding 
structure for that function. “Under this second 
step, ‘structure disclosed in the specification is “corresponding” 
structure only if the specification or prosecution 
history clearly links or associates that structure to the 
function recited in the claim.’” Med. Instrumentation & 
Diagnostics Corp. v. Elekta AB, 344 F.3d 1205, 1210 [68 
USPQ2d 1263, 1267] (Fed. Cir. 2003) (quoting B. Braun 





Med. Inc. v. Abbott Labs., 124 F.3d 1419, 1424 [43 
USPQ2d 1896, 1900] (Fed. Cir. 1997)).

If the specification defines what is meant by the limitation 
for the purposes of the claimed invention, the 
examiner should interpret the limitation as having that 
meaning. If no definition is provided, some judgment 
must be exercised in determining the scope of the limitation. 
See, e.g., B. Braun Medical, Inc. v. Abbott 
Labs., 124 F.3d 1419, 1424, 43 USPQ2d 1896, 1900 
(Fed. Cir. 1997) (“We hold that, pursuant to [35 
U.S.C. 112, sixth paragraph], structure disclosed in 
the specification is ‘corresponding’ structure only if 
the specification or prosecution history clearly links 
or associates that structure to the function recited in 
the claim. This duty to link or associate structure to 
function is the quid pro quo for the convenience of 
employing 112, paragraph 6.” The court refused to 
interpret a means-plus-function limitation as corresponding 
to a disclosed valve seat structure, as argued 
by patentee, since there was no indication in the specification 
or prosecution history that this structure corresponds 
to the recited function, and there was an 
explicitly clear association between that function and 
a traverse cross section bar structure disclosed in the 
specification.).