## United States Court of Appeals for the Federal Circuit
03-1269, -1286

EDWARD H. PHILLIPS, Plaintiff-Appellant,

v.

AWH CORPORATION, HOPEMAN BROTHERS, INC., and LOFTON CORPORATION, Defendants-Cross Appellants.

Carl F. Manthei , Attorney at Law, of Boulder, Colo rado, argued for plaintiff-appellant. Mark W. Fischer , Faegre & Benson LLP, of Boulder, Colorado, argued for defendantscross appellants. With him on the brief were Neal S. Cohen and Peter J. Kinsella . Of counsel on the brief were Maurice M. Klee , Law Office of Maurice M. Klee, Ph.D., Fairfield, Connecticut, and Kenneth C. Bass, III , Sterne, Kessler, Goldstei n & Fox, of Washington, DC. Of counsel was Scott E. Holwick , Faegre & Benson LLP. John M. Whealan , Solicitor, United States Patent and Trademark Office, of Alexandria, Virginia, argued for amicus curiae United States. With him on the brief were James A. Toupin , General Counsel; Cynthia C. Lynch ; Linda Moncys Isacson ; and Thomas W. Krause , Associate Solicitors. Of counsel on the brief were Peter D. Keisler , Assistant Attorney General; John J. Fargo , Director, Commercial Litigation Branch, and Anthony J. Steinmeyer , Attorney, Appellate Staff, Civ il Division, United States Department of Justice, of Washington, DC; and William E. Kovacic , General Counsel, and Suzanne T. Michel , Chief Counsel for Intellectual Property, Federal Trade Commission, of Washington, DC. Robert L. Baechtold , Fitzpatrick, Cella, Harper & Sc into, of New York, New York, for amici curiae Novartis Pharmaceuticals Corpor ation, et al. With him on the brief were Nicholas N. Kallas , Stevan J. Bosses , and Brian V. Slater

. Paul H. Berghoff , McDonnell Boehnen Hulbert & Berghoff LLP, of Chicago, Illinois, for amicus curiae Intellectual Property Owners Association. With him on the brief was Joshua R. Rich . Of counsel on the brief was J. Jeffery Hawley , President, Intellectual Property Owners Association, of Wash ington, DC. Of counsel was Herbert C. Wamsley , Intellectual Property Owners Association.Charles W. Bradley , Rader, Fis h man & Grauer, PLLC, of Bloomfield Hills , Michigan, for amicus curiae Cha r les W. Bradley. Henry C. Bunsow , Howrey Simon Arnold & White, LLP, of San Francisco, California, for amicus curiae AD HOC Committee of P a tent Owners in the Wireless Industry. With him on the brief were Robert C. Laurenson and David W. Long . Of counsel on the brief were Robert D. Yeager , Thomas J. Edgington , and Mark G. Knedeis e n , Kirkpatrick & Lockhart LLP, of Pittsburgh, Pennsylvania. Alexander C. Johnson, Jr. , Marger, Johnson & McCollom, P.C., of Portland, Oregon, for amicus curiae Oregon Pa tent Law Association. Alice A. K i pel , Stept oe & Johnson, LLP, of Washington, DC, for amicus curia e International Trade Commission Trial Lawy e rs Association. Stephen P. McNamara , St. Onge Stewar d Johnston & Reens LLC, of Stamford, Connectic u t, for amicus curiae Connecticut Intelle ctual Property Law Asso ciation. With him on the brief was Richard J. Basile . Of counsel on the brief were Willia m J. Sapone , Coleman Sudol Sapone, P.C ., of Bridgeport, Connecticut, Michael J. Rye , Cantor Colbur n LLP, of Bloomfield, Connecticut. Douglas E. Olson , Paul, Hastings, Janofsky & Walker, LLP, of San Diego, California, for amicus curiae San Diego Intellectual Pr operty Law Association. With him on the brief were Kurt M. Kjelland , John E. Peterson , and April M. Alex . Of counsel on the brief were Ned A. Israelsen , Knobbe Martens Olson & Bear, LLP , of San Diego, Califor nia, and William L. Respess , Nanogen, Inc., of San Diego, California. John Will Ongman , Barnes & Thornburg LLP, of W a sh ington, DC, for am icus curiae Biotechnology Industry Organization. With him on the brief was A lice O. Martin , of Chic ago, Illino i s. Of counsel on the brief was Stephan E. Lawton , Vice President and General Counsel, Biotechnology Industry Or ganization, of Washington, DC. Steve Z. Szczepans ki , Kelley Drye & Warren LLP, of Chicago, Illinois, for amicus curiae Parus Holdings, Inc. With him on the brief was Mary Jo Boldingh

. Frederick A. Tecce , McShea T e cce, P.C., of Philadelp hia, Pennsylvania, for amici curiae McShea Tecce, P.C., et al. Michael P. Dougherty , Morgan & Finnegan, L.L.P., of New York, New York, for amicus curiae Federal Circuit Bar Associat ion. Of counsel on the brief was Ch arles F. Schill , President, Federal Circuit Bar A ssociation, of Washington, DC. Edward D. Manzo , Cook, Alex, McFarron, Manzo, Cummings & Mehle r , Ltd., of Chicago, Illinois, for amicus curiae The Intellec tual Prop erty Law Associ ation of Chicago. Of counsel with him on the brief were Patrick G. Burns , Greer, Burns & Crain, Ltd., of Chicago, Illino i s, Dean A. Monc o , Wood, Phillips, Katz, Clark & M o rtimer, of Chicago, Illinois, Bra d ford

2P. Lyerla , Marshall, Gerstein & Borun, of Chicago, Illinois, and Timothy J. Vezeau , Katten Muchin Za vis Rosen m an, of Chicago, Illino i s. Maxim H. Waldbaum , Schiff Har d in LL P, of New York, New Yor k , for amicus curia e Federation Internationale Des C onseils En Propriete Industrie lle. Of counsel on the brief was John P. Sutton , of San Francisco, California. Michael R. Dzwonczy k , Sughrue Mion, PLLC, of Washi ngton, DC, for amicus curia e Sughrue M i on, PLLC. With him on the brief were Frank L. Bernstein of Mountain View, California, and Brandon M. White of Washington, DC. Sharon A. Israel , Je nkens & Gilchrist, P.C., of Ho us ton, Texas, for amicus curiae Houston Intellectual Property Law Assoc i ation. Of counsel on the brief were Jeremy P. Welch , Jonathan M. Pierce , and Jeffrey L. Johnson , Conley Rose, P.C., o f Houston, Tex a s. George C. Summerfield, Jr. , Stadheim & Grear, of Chicago, Illinois, for amici curiae The Wisconsin Alumni Res ear ch Foundation, et al. Wi th him on the brief were Joseph A. Grear and Keith A. Vo gt

. Bruce M. Wexler , Fitzpatrick, Cella, Harpe r & Scin to, of New Y o rk, New York, for amicus curiae New York Intellectual Property Law Association. With him on the brief were Matthew S. Seidner and John D. Murnane

. Rick D. Nydegger , Workman Nydegger, of Salt Lake City, Ut ah, for amicus curiae American Intellectual Property Law Associ ation. With him on the brief was David R. Todd

. Of counsel on the brief were Denise W. DeFranco , Foley Hoag LLP, of Boston, Massachusetts, and J oseph R. Re and Joseph S. Cianfrani , Knobbe Martens Olson & Bear, of Irvine, C a lifornia. Christopher Landau , Kirklan d & Ellis LL P, of Wash ington, DC, for amicus curiae Infineon Technologies North America Corp . With him o n the brief were John C. O’Quinn , of Washington, DC, and John M. D e smarais , Gregory S. Arovas , and Michael P. Stadnick , of New York, New York. Mark I. Levy , Kilpatrick Stockton, LLP, of Wash ington, DC, for amicus curia e Association of Corpor ate Couns e l. With him on the brief were Anthony B. Ask e w and Eugene B. Joswick , of Atlanta, Georgia. Of counsel on the brief were Frederick J. Krebs and Susan Hackett of Washington, DC, Ne lson A. B lis h , Eastman Kodak, of Rochester, New York, John W. Hogan, Jr. , Wyeth, of Madison, New Jersey, and Taraneh Maghame , Hewlett Packard, of Cupertino, California. Mark A. Le mley , Keker & VanNest, LLP, of San Franci sco, California, for ami c i curiae Intel Corporation, et al

. With him on the brief were Brian L. Ferrall an d Ryan M. Kent

.

3Erik Pau l Belt , Bromberg and Sunstein LLP, of Bo ston, Massachusetts, for amicus curiae Bost on Patent Law Assoc i ati on. Of counsel on the brief was Peter Corless , Edwards and Angell LLP, of Boston, Massachusetts. Susan M. Dadio , Bur n s, Doane, Sweck e r & Mathis, L. L.P., of Alexandria, Virgin ia, for amicus curiae Bar As sociation of the District of Columbia – Patent, Trademark & Copyright Section. Of counsel on the brief was Ly nn E. Eccleston , The Eccleston Law Firm, of Washingto n , DC. W. Thomas McGough, Jr. , Reed Smith LLP, of Pittsburgh, Pennsylvania, for amicus curiae Medrad, Inc. With him on the brief were Frede rick H. Colen and Bar r y J. Coyne . O f counsel on the brief was Gregory L. Bradley , Medrad, Inc., o f I ndianola, Pennsylvania. Peter A. Sullivan , Hughes Hubbard & Reed LLP, of New York, New York, for amicus curiae The Association of the Bar of the City of New York. Of counsel on the brief was Catriona M. Collins , Cowan, Liebowitz & Latman, P.C., of New York, New York. Anthony R. Zeuli , Merchant & Gould P.C., of Mi nneapolis, Minnesota, for amicus curiae Ass o ciation of Patent Law Fi rms. With him on the brief were Thomas J. Leach, III and Rach e l Clark-Hug hey . Of counsel on the brief were Scott P. McBride and Christopher R. Carroll , McAndrews, Held & Malloy Lt d., of Chicago, Illinois, and Eric R. M o ran , McDonnell, Boehnen, Hulb ert & Bergho ff LLP, of Chicago, Illinois. Daniel B. Ravicher , Public Patent Foundation, of New York, New York, for amicus curiae Public Patent Foundation. Theodore T. Herhold , Townsend and Townsend and Crew LLP, of Palo Alto, California, for amici curiae VISA U.S.A. In c ., et al. With hi m on the brief were Daniel J. Furniss , Susan M. Spaeth , Madis on C. Jellin s , and Mark G. Sandbaken

. Mark A. Goldstein , SoCal IP Law Group, of Westlake Village, California, for amicus curiae Conejo Valley Bar Associati on. With him on the brief were Steven C. Sereboff and Joel G. Landau

. Robert J. Grey, Jr. , President, American Bar Associat ion, of Chicago, Illinois, for amicus curiae American Bar Associat ion. With him on the brief was William L. LaFuze . Of counsel on the brief were Donald R. Dunner and Ri chard L. R a i ney , Finnegan, Henders on, Farabow, Garrett & D unner, L. L.P., of Washington, DC. R. Polk Wagner , University of Pennsylvan i a Law Sc hool, of Philadelphia, Pennsylv a nia, for ami c us curiae Patent Law Professors R. Polk Wagner, et al. Joshua D. Sarnoff , Washington College of Law, Amer ican Univer sity, of Washington, DC, for ami c i curiae Consumers Union, et al.

4Laura M. S l enzak , Siemens Corporation, of Auburn Hills, Michig an, for amicus curia e The State Bar of Michigan, Intellectual Property Law Section, joined in the brief of the New York Intellectual Property Law Association. Lea Hall Speed , Bak e r, Donels on, Bearman & Cald well, of Memphis, Tennessee, for amicus curiae Tennes see Bar Association, joined in the brief of the New York Intellec t ual Property Law Association.

Appealed from: United States Distric t Court for the Distri c t of Colorado Judge Marcia S. Krieger

5

## United States Court of Appeals for the Federal Circuit

03-1269, -1286 EDWARD H. PHILLIPS, Plaintiff-Appellant,

v. AWH CORPORATION, HOPEMAN BROTHERS, INC., and LOFTON CORPORATION, Defendants-Cross Appellants.

___________________________ DECIDED: July 12, 2005

___________________________ Before MICHEL, Chief Judge , NEWMAN, MAYER, LOURIE, CLEVENGER, RADER, SCHALL, BRYSON, GAJARSA, LINN, DYK, and PROST, Circuit Judges

. Opinion for the court filed by Circuit Judge BRYSON, in which Chief Judge MICHEL and Circuit Judges CLEVENGER, RADER, SCHALL, GA JARSA, LINN, DYK, and PROST join; and in which Circuit Judge LOURIE joins with respect to parts I, II, III, V, and VI; and in which Circuit Judge NEWMAN joins with respect to parts I, II, III, and V. Opinion concurring in part and dissenting in part filed by Circuit Judge LOURIE, in which Circuit Judge NEWMAN joins. Dissenting opinion filed by Circuit Judge MAYER, in which Circuit Judge NEWMAN joins. BRYSON, Circuit Judge

. Edward H. Phillips invented modular, steel-shell panels that can be welded together to form vandalism-resistant walls. T he panels are especially useful in building prisons because they are load-bearing and im pact-resistant, while also insulating against fire and noise. Mr. Phillips obtained a pat ent on the invention, U.S. Patent No. 4,677,798 (“the ’798 patent”), and he subsequently entered into an arrangement with03-1269, -1286 2 AWH Corporation, Hopeman Brot hers, Inc., and Lofton Corpor ation (collectively “AWH”) to market and sell the panels. That arrangem ent ended in 1990. In 1991, however, Mr. Phillips received a sales brochure from AW H that suggested to him that AWH was continuing to use his trade secrets and patent ed technology without his consent. In a series of letters in 1991 and 1992, Mr. Phillip s accused AWH of pat ent infringement and trade secret misappropriation. Corres pondence between the parties regarding the matter ceased after that time. In February 1997, Mr. Phillips brought suit in the United States District Court for the District of Colorado c harging AWH with misappropriati on of trade secrets and infringement of claims 1, 21, 22, 24, 25, and 26 of the ’798 patent. Phillips v. AWH Corp. , No. 97-N-212 (D. Colo.). The district court dismissed the trade secret misappropriation claim as barred by Colorado’ s three-year statute of limitations. With regard to the patent infringement i ssue, the district court focused on the language of claim 1, which recites “furt her means disposed inside the shell for increasing its load bearing capacity comprising in ternal steel baffles extending inwardly from the steel shell walls.” The court interpreted that language as “a means . . . for performing a specified function,” subject to 35 U.S.C. § 112, paragraph 6, which provides that such a claim “shall be cons trued to cover the corresponding structure, material, or acts described in the specific ation and equivalents thereof.” Looking to the specification of the ’798 paten t, the court noted that “every textual reference in the Specification and its diagrams show baffle deployment at an angle other than 90° to the wall faces” and that “placement of the baffles at such angles creates an intermediate interlocking, but not solid, inte rnal barrier.” The district court therefore ruled that, for03-1269, -1286 3 purposes of the ’798 patent, a baffle must “extend inward from the steel shell walls at an oblique or acute angle to the wall face” and mu st form part of an interlocking barrier in the interior of the wall module. Because Mr. Phillips could not prove infringement under that claim construction, the district court granted summary judgment of noninfringement. Mr. Phillips appealed with respect to both the trade se cret and patent infringement claims. A panel of th is court affirmed on both issues. Phillips v. AWH Corp. , 363 F.3d 1207 (Fed. Cir. 2004). As to the trade secret claim, the panel unanimously upheld the district court’s ruling t hat the claim was barred by the applicable statute of limitations. Id. at 1215. As to the patent in fringement claims, the panel was divided. The majority sustained the di strict court’s summary judgment of noninfringement, although on different grounds . The dissenting judge would have reversed the summary judgment of noninfringement. The panel first determined that because t he asserted claims of the ’798 patent contain a sufficient recitation of structure, the district cour t erred by construing the term “baffles” to invoke the “means-plus-function” claim format authorized by section 112, paragraph 6. Id. at 1212. Nonetheless, the panel concluded that the patent uses the term “baffles” in a restrictive manner. Ba sed on the patent’s wri tten description, the panel held that the claim term “ baffles” excludes structures that extend at a 90 degree angle from the walls. The panel noted that t he specification repeatedly refers to the ability of the claimed baffles to deflect projectiles and that it describes the baffles as being “disposed at such angles that bullets which might penetrate the outer steel panels are deflected.” ’798 paten t, col. 2, ll. 13-15; see also id. at col. 5, ll. 17-19 (baffles are “disposed at angles which tend to deflect the bullets”). In addition, the panel observed03-1269, -1286 4 that nowhere in the patent is there any disclosure of a ba ffle projecting from the wall at a right angle and that baffles ori ented at 90 degrees to the wall we re found in the prior art. Based on “the specification’s explicit descriptions,” the panel concluded “that the patentee regarded his invention as panels provid ing impact or projectile resistance and that the baffles must be orient ed at angles other than 90°.” Phillips , 363 F.3d at 1213. The panel added that the patent specification “is intended to support and inform the claims, and here it makes it unmistakably clear that the invention involves baffles angled at other than 90°.” Id. at 1214. The panel therefore uphel d the district court’s summary judgment of noninfringement. The dissenting judge argued t hat the panel had improperly limited the claims to the particular embodiment of t he invention disclosed in the specification, rather than adopting the “plain meaning” of the term “baffl es.” The dissenting judge noted that the parties had stipulated that “baffles” are a “m eans for obstructing, impeding, or checking the flow of something,” and that the panel majority had agreed that the ordinary meaning of baffles is “something for deflecting, checking, or otherwise regulating flow.” Phillips , 363 F.3d at 1216-17. In the dissent’s view, nothing in the specification redefined the term “baffles” or constituted a disclaimer specifically limiting the term to less than the full scope of its ordinary m eaning. Instead, the dissenting judge contended, the specification “merely identif ies impact resistance as one of several objectives of the invention.” Id. at 1217. In sum, the dissent concluded that “there is no reason to supplement the plai n meaning of the claim language with a limitation from the preferred embodiment.” Id. at 1218. Consequently, the dissenting judge argued that the court should have adopted the general purpose dictionar y definition of the term03-1269, -1286 5 baffle, i.e., “something for deflecting, checking, or otherwise regulating flow,” id. , and therefore should have reversed the summary judgment of noninfringement. This court agreed to rehear the appeal en banc and vaca ted the judgment of the panel. Phillips v. AWH Corp. , 376 F.3d 1382 (Fed. Cir. 2004). We now affirm the portion of the district court’ s judgment addressed to the tr ade secret misappropriation claims. However, we reverse the portion of the court’s judgment addressed to the issue of infringement.
I Claim 1 of the ’798 patent is representative of the asse rted claims with respect to the use of the term “baffles.” It recites: Building modules adapted to fit together for construction of fire, sound and impact resistant security barriers and rooms for use in securing records and persons, comprising in combinati on, an outer shell . . . , sealant means . . . and further means disposed inside the shell for increasing its load bearing capacity comprising internal steel baffles extending inwardly from the steel shell walls. As a preliminary matter, we agree with t he panel that the term “baffles” is not means-plus-function language that invokes 35 U. S.C. § 112, paragraph 6. To be sure, the claim refers to “means disposed inside the shell for increasing its load bearing capacity,” a formulation that would ordinar ily be regarded as invoking the means-plusfunction claim format. However, the claim spec ifically identifies “internal steel baffles” as structure that performs the recited f unction of increasing the shell’s load-bearing capacity. In contrast to the “load bearing m eans” limitation, the reference to “baffles” does not use the word “means,” and we have hel d that the absence of that term creates a rebuttable presumption that sect ion 112, paragraph 6, does not apply. See03-1269, -1286 6 Personalized Media Communications, LLC v. Int’l Trade Comm’n , 161 F.3d 696, 703-04 (Fed. Cir. 1998). Means-plus-function claiming applies only to purely functional limitations that do not provide the struct ure that performs the recited function. See Watts v. XL Sys., Inc. , 232 F.3d 877, 880-81 (Fed. Cir. 2000). While the baffles in the ’798 patent are clearly intended to perform several functions, the term “baffles” is nonetheless structural; it is not a purely functional placeholder in which stru cture is filled in by the specification. See TurboCare Div. of Demag Delaval Tur bomachinery Corp. v. Gen. Elec. Co. , 264 F.3d 1111, 1121 (Fed. Cir. 2001) (reasoning that nothing in the specification or prosecution history suggests that the pat entee used the term “compressed spring” to denote any structure that is capable of performing the specified function); Greenberg v. Ethicon Endo-Surgery, Inc. , 91 F.3d 1580, 1583 (Fed. Cir. 1996) (construing the term “detent mechanism” to refer to particular st ructure, even though the term has functional connotations). The claims and the specificat ion unmistakably establish that the “steel baffles” refer to particular ph ysical apparatus. The claim characterizes the baffles as “extend[ing] inwardly” from the steel shell walls, which plainly implies that the baffles are structures. The specification likewise makes cl ear that the term “steel baffles” refers to particular internal wall struct ures and is not simply a general description of any structure that will perform a particular function. See, e.g. , ’798 patent, col. 4, ll. 25-26 (“the load bearing baffles 16 are optionally used with longer panels”); id. , col. 4, ll. 49-50 (opposing panels are “compressed between the flange 35 and the baffle 26”). Because the term “baffles” is not subject to section 112, paragraph 6, we agree with the panel that the district court erred by limiting the term to corresponding structures disclosed in the03-1269, -1286 7 specification and their equivalents. Accord ingly, we must determine the correct construction of the structural term “ baffles,” as used in the ’798 patent.
II The first paragraph of section 112 of the Pa tent Act, 35 U.S.C. § 112, states that the specification shall contain a written description of the invention, and of the manner and process of making and using it, in su ch full, clear, concise, and exact terms as to enable any person skilled in t he art to which it pertains . . . to make and use the same . . . . The second paragraph of section 112 pr ovides that the specification shall conclude with one or more clai ms particularly pointing out and distinctly claiming the subject matte r which the applicant regards as his invention. Those two paragraphs of section 112 frame the issue of claim interpretation for us. The second paragraph requires us to look to the language of the claims to determine what “the applicant regar ds as his invention.” On the other hand, the first paragraph requires that the specif ication describe the invention set forth in the claims. The principal question that this case presents to us is the extent to which we should resort to and rely on a patent’s specification in seeking to ascertai n the proper scope of its claims. This is hardly a new question. The role of the specification in claim construction has been an issue in patent law dec isions in this country for nearly two centuries. We addressed the relationship betw een the specification and the cl aims at some length in our en banc opinion in Markman v. Westview Instruments, Inc. , 52 F.3d 967, 979-81 (Fed. Cir. 1995) (en banc), aff’d , 517 U.S. 370 (1996). We again summarized the applicable principles in Vitronics Corp. v. Conceptronic, Inc. , 90 F.3d 1576 (Fed. Cir.03-1269, -1286 8 1996), and more recently in Innova/Pure Water, Inc. v. Sa fari Water Filtration Systems, Inc. , 381 F.3d 1111 (Fed. Cir. 2004). What we said in those cases bears restating, for the basic principles of claim constructi on outlined there are still applicable, and we reaffirm them today. We have also previous ly considered the use of dictionaries in claim construction. What we have said in that regard requi res clarification.
A It is a “bedrock principle” of patent law that “the clai ms of a patent define the invention to which the patentee is entitled the right to exclude.” Innova , 381 F.3d at 1115; see also Vitronics , 90 F.3d at 1582 (“we look to the words of the claims themselves . . . to define the scope of the patented invention”); Markman , 52 F.3d at 980 (“The written description part of the specification itself does not delimit the right to exclude. That is the function and purpose of claims.”). That principle has been recognized since at least 1836, when Congre ss first required that the specification include a portion in which the inventor “shall particularly specify and point out the part, improvement, or combination, which he claims as his own invention or discovery.” Act of July 4, 1836, ch. 357, § 6, 5 Stat. 117, 119. In the following years, the Supreme Court made clear that the claims are “of primary importance, in the effort to ascertain precisely what it is that is patented.” Merrill v. Yeomans , 94 U.S. 568, 570 (1876). Because the patentee is required to “define precisely what hi s invention is,” the Court explained, it is “unjust to the public, as well as an evasion of the law, to construe it in a manner different from the pl ain import of its terms.” White v. Dunbar , 119 U.S. 47, 52 (1886); see also Cont’l Paper Bag Co. v. E. Paper Bag Co. , 210 U.S. 405, 419 (1908) (“the claims measure the invention”); McCarty v. Lehigh Valley R.R. Co. , 160 U.S. 110,03-1269, -1286 9 116 (1895) (“if we once begin to include elements not mentioned in the claim, in order to limit such claim . . . , we shoul d never know where to stop”); Aro Mfg. Co. v. Convertible Top Replacement Co. , 365 U.S. 336, 339 (1961) (“the claims made in the patent are the sole measure of the grant”). We have frequently stated that the words of a claim “are generally given their ordinary and customary meaning.” Vitronics , 90 F.3d at 1582; see also Toro Co. v. White Consol. Indus., Inc. , 199 F.3d 1295, 1299 (Fed. Cir. 1999); Renishaw PLC v. Marposs Societa’ per Azioni , 158 F.3d 1243, 1249 (Fed. Cir. 1998). We have made clear, moreover, that the ordinary and customary meaning of a claim term is the meaning that the term would have to a person of ordinary skill in the art in question at the time of the invention, i. e., as of the effective filing date of the patent application. See Innova , 381 F.3d at 1116 (“A court construing a pat ent claim seeks to accord a claim the meaning it would have to a person of ordinary skill in the art at the time of the invention.”); Home Diagnostics, Inc. v. LifeScan, Inc. , 381 F.3d 1352, 1358 (Fed. Cir. 2004) (“customary meaning” refers to the “c ustomary meaning in [the] art field”); Ferguson Beauregard/Logic Controls v. Mega Sys., LLC , 350 F.3d 1327, 1338 (Fed. Cir. 2003) (claim terms “are examined through the viewing glass of a person skilled in the art”); see also PC Connector Solutions LLC v. SmartDisk Corp. , 406 F.3d 1359, 1363 (Fed. Cir. 2005) (meaning of cl aim “must be interpreted as of [the] effective filing date” of the patent application); Schering Corp. v. Amgen Inc. , 222 F.3d 1347, 1353 (Fed. Cir. 2000) (same). The inquiry into how a person of ordinar y skill in the art understands a claim term provides an objective baseline from wh ich to begin claim interpretation. See Innova ,03-1269, -1286 10 381 F.3d at 1116. That star ting point is based on the well-settled understanding that inventors are typically persons skilled in the field of the invention and that patents are addressed to and intended to be read by ot hers of skill in the pertinent art. See Verve, LLC v. Crane Cams, Inc. , 311 F.3d 1116, 1119 (Fed. Cir. 2002) (patent documents are meant to be “a concise statement for persons in the field”); In re Nelson , 280 F.2d 172, 181 (CCPA 1960) (“The descriptions in patent s are not addressed to the public generally, to lawyers or to judges, but, as sect ion 112 says, to those skilled in the art to which the invention pertains or with wh ich it is most nearly connected.”). Importantly, the person of ordinary skill in the art is deemed to read the claim term not only in the context of the particular claim in which the disputed term appears, but in the context of the entir e patent, including the specificat ion. This court explained that point well in Multiform Desiccants, Inc. v. Medzam, Ltd. , 133 F.3d 1473, 1477 (Fed. Cir. 1998): It is the person of ordi nary skill in the field of the invention through whose eyes the claims are construed. Such person is deemed to read the words used in the patent document s with an understanding of their meaning in the field, and to have k nowledge of any special meaning and usage in the field. The inventor’s words that are used to describe the invention—the inventor’s le xicography—must be understood and interpreted by the court as they would be understood and interpreted by a person in that field of technology . Thus the court starts the decisionmaking process by reviewing the same resources as would that person, viz ., the patent specification and the prosecution history. See also Medrad, Inc. v. MRI Devices Corp. , 401 F.3d 1313, 1319 (Fed. Cir. 2005) (“We cannot look at the ordinary meaning of the term . . . in a vacuum. Ra ther, we must look at the ordinary meaning in t he context of the written de scription and the prosecution history.”); V-Formation, Inc. v. Benetton Group SpA , 401 F.3d 1307, 1310 (Fed. Cir. 2005) (intrinsic record “usually provides the technological and temporal context to03-1269, -1286 11 enable the court to ascertain the meaning of t he claim to one of ordinary skill in the art at the time of the invention”); Unitherm Food Sys., Inc. v. Swift-Eckrich, Inc. , 375 F.3d 1341, 1351 (Fed. Cir. 2004) (proper definition is the “definiti on that one of ordinary skill in the art could ascertain from the intrinsic evidence in the record”).
B In some cases, the ordinary meani ng of claim language as understood by a person of skill in the art may be readily apparent even to lay judges, and claim construction in such cases involves littl e more than the applic ation of the widely accepted meaning of comm only understood words. See Brown v. 3M , 265 F.3d 1349, 1352 (Fed Cir. 2001) (holding that the claims did “not require elaborate interpretation”). In such circumstances, general purpose dict ionaries may be helpful. In many cases that give rise to litigation, however, det ermining the ordinary and customary meaning of the claim requires examination of terms that have a particular meaning in a field of art. Because the meaning of a claim term as under stood by persons of skill in the art is often not immediately apparent, and bec ause patentees frequently use terms idiosyncratically, the court looks to “those sources available to the public that show what a person of skill in the art would have understood disputed claim language to mean.” Innova , 381 F.3d at 1116. Those s ources include “the words of the claims themselves, the remainder of the specific ation, the prosecution hist ory, and extrinsic evidence concerning relevant scientific principles, the meaning of technical te rms, and the state of the art.” Id. ; see also Gemstar-TV Guide Int’l, Inc. v. Int’l Trade Comm’n , 383 F.3d 1352, 1364 (Fed. Cir. 2004); Vitronics , 90 F.3d at 1582-83; Markman , 52 F.3d at 979-
80.03-1269, -1286 12 1 Quite apart from the written description and the prosecution history, the claims themselves provide substantial guidance as to the meaning of particular claim terms. See Vitronics , 90 F.3d at 1582; see also ACTV, Inc. v. Walt Disney Co. , 346 F.3d 1082, 1088 (Fed. Cir. 2003) (“the context of the surr ounding words of the claim also must be considered in determining the ordinary and customary meaning of those terms”). To begin with, the context in which a term is used in the asserted claim can be highly instructive. To take a simple example, the claim in this case refers to “steel baffles,” which strongly implies that the te rm “baffles” does not inherently mean objects made of steel. This court’s cases provide numerous similar examples in which the use of a term within the claim provides a firm basis for construing the term. See, e.g. , Mars, Inc. v. H.J. Heinz Co. , 377 F.3d 1369, 1374 (Fed. Cir. 2004) (claim term “ingredients” construed in light of the use of the term “mixture” in the same claim phrase); Process Control Corp. v. HydReclaim Corp. , 190 F.3d 1350, 1356 (Fed. Cir. 1999) (claim term “discharge rate” construed in light of the us e of the same term in another limitation of the same claim). Other claims of the patent in question, both asserted and unasserted, can also be valuable sources of enlightenment as to the meaning of a claim term. Vitronics , 90 F.3d at 1582. Because claim terms are normally used consist ently throughout the patent, the usage of a term in one claim can often illuminate the meaning of the same term in other claims. See Rexnord Corp. v. Laitram Corp. , 274 F.3d 1336, 1342 (Fed. Cir. 2001); CVI/Beta Ventures, Inc. v. Tura LP , 112 F.3d 1146, 1159 (Fed. Cir. 1997). Differences among claims can also be a useful guide in understanding the meaning of03-1269, -1286 13 particular claim terms. See Laitram Corp. v. Rexnord, Inc. , 939 F.2d 1533, 1538 (Fed. Cir. 1991). For example, the presence of a dependent claim that adds a particular limitation gives rise to a pres umption that the limit ation in question is not present in the independent claim. See Liebel-Flarsheim Co. v. Medrad, Inc. , 358 F.3d 898, 910 (Fed. Cir. 2004).
2 The claims, of course, do not stand alone. Rather, they are part of “a fully integrated written instrument,” Markman , 52 F.3d at 978, consisting principally of a specification that concludes with the claims. For that r eason, claims “must be read in view of the specification, of which they are a part.” Id. at 979. As we stated in Vitronics , the specification “is always highly relevant to the claim construction analysis. Usually, it is dispositive; it is the single best guide to the meaning of a disput ed term.” 90 F.3d at
1582. This court and its predecessors have l ong emphasized the importance of the specification in claim construction. In Autogiro Co. of America v. United States , 384 F.2d 391, 397-98 (Ct. Cl. 1967), the Court of Cla ims characterized the specification as “a concordance for the claims,” based on the statutory requirem ent that the specification “describe the manner and process of making and using” the patented invention. The Court of Customs and Patent Appeals made a similar point. See In re Fout , 675 F.2d 297, 300 (CCPA 1982) (“Claims must always be read in light of the spec ification. Here, the specification makes plain what the appe llants did and did not invent . . . .”). Shortly after the creation of this cour t, Judge Rich wrote that “[t]he descriptive part of the specification aids in asce rtaining the scope and meaning of the claims03-1269, -1286 14 inasmuch as the words of the claims must be based on the description. The specification is, thus, the primary basis for construing the claims.” Standard Oil Co. v. Am. Cyanamid Co. , 774 F.2d 448, 452 (Fed. Cir. 1985). On numerous occasions since then, we have reaffirmed that point, stati ng that “[t]he best sour ce for understanding a technical term is the specification from whic h it arose, informed, as needed, by the prosecution history.” Multiform Dessicants , 133 F.3d at 1478; Metabolite Labs., Inc. v. Lab. Corp. of Am. Holdings , 370 F.3d 1354, 1360 (Fed. Cir. 2004) (“In most cases, the best source for discerning the proper context of claim terms is the patent specification wherein the patent applicant de scribes the invention.”); see also, e.g. , Kinik Co. v. Int’l Trade Comm’n , 362 F.3d 1359, 1365 (Fed. Cir. 2004) (“The words of patent claims have the meaning and scope with wh ich they are used in the specification and the prosecution history.”); Moba, B.V. v. Diamond Automation, Inc. , 325 F.3d 1306, 1315 (Fed. Cir. 2003) (“[T]he best indicator of cl aim meaning is its usage in context as understood by one of skill in the art at the time of invention.”). That principle has a long pedigree in Supreme Court decisions as well. See Hogg v. Emerson , 47 U.S. (6 How.) 437, 482 (1848) (the specification is a “component part of the patent” and “is as much to be considered with the [letters patent] in construing them, as any paper referred to in a deed or other contract”); Bates v. Coe , 98 U.S. 31, 38 (1878) (“in case of doubt or ambiguity it is proper in all cases to refer back to the descriptive portions of the specification to aid in solving the doubt or in ascertaining the true intent and meaning of the language employed in the claims”); White v. Dunbar , 119 U.S. 47, 51 (1886) (s pecification is appropriately resorted to “for the purpose of better understanding the meaning of the claim”); Schriber-Schroth Co. v.03-1269, -1286 15 Cleveland Trust Co. , 311 U.S. 211, 217 (1940) (“The claims of a patent are always to be read or interpreted in light of its specifications.”); United States v. Adams , 383 U.S. 39, 49 (1966) (“[I]t is fundamental t hat claims are to be construed in the light of the specifications and both are to be read with a view to ascertaining the invention.”). The importance of the spec ification in claim constr uction derives from its statutory role. The close kinship between the written description and the claims is enforced by the statutory r equirement that the specific ation describe the claimed invention in “full, clear, concise, and ex act terms.” 35 U.S.C. § 112, para. 1; see Netword, LLC v. Centraal Corp. , 242 F.3d 1347, 1352 (Fed. Cir. 2001) (“The claims are directed to the invention that is described in the specification; they do not have meaning removed from the context fr om which they arose.”); see also Markman v. Westview Instruments, Inc. , 517 U.S. 370, 389 (1996) (“[A claim] term can be defined only in a way that comports with the instrument as a whole.”). In light of the statutory directive that the inventor prov ide a “full” and “exact” description of the claimed invention, the specification necessarily informs the proper construction of the claims. See Merck & Co. v. Teva Pharms. USA, Inc. , 347 F.3d 1367, 1371 (Fed. Cir. 2003) (“A fundamental rule of claim construction is that terms in a patent document are construed with the meaning with which they are pr esented in the patent document. Thus claims must be construed so as to be consist ent with the specification, of which they are a part.”) (citations omitted). In Renishaw , this court summarized that point succinctly: Ultimately, the interpretation to be given a term can only be determined and confirmed with a full under standing of what the inventors actually invented and intended to envelop with the claim. The construction that stays true to the claim language and most naturally aligns with the patent’s description of the inventi on will be, in the end, the correct construction.03-1269, -1286 16 158 F.3d at 1250 (citations omitted). Consistent with that general principle, our cases recogni ze that the specification may reveal a special definition given to a cl aim term by the patentee that differs from the meaning it would otherwise possess. In such cases, the inventor’s lexicography
governs. See CCS Fitness, Inc. v. Brunswick Corp. , 288 F.3d 1359, 1366 (Fed. Cir. 2002). In other cases, the specification may reveal an intentional disclaimer, or disavowal, of claim scope by t he inventor. In that instanc e as well, the inventor has dictated the correct claim sc ope, and the inventor’s intent ion, as expressed in the specification, is regar ded as dispositive. See SciMed Life Sys., Inc. v. Advanced Cardiovascular Sys., Inc. , 242 F.3d 1337, 1343-44 (Fed. Cir. 2001). The pertinence of the specif ication to claim construction is reinforced by the manner in which a patent is issued. The Patent and Trademark Office (“PTO”) determines the scope of claims in patent applications not solely on the basis of the claim language, but upon giving claims their broadest reasonable construction “in light of the specification as it would be interpreted by one of ordinar y skill in the art.” In re Am. Acad. of Sci. Tech. Ctr. , 367 F.3d 1359, 1364 (Fed. Cir. 2004). Indeed, the rules of the PTO require that application claims must “c onform to the invention as set forth in the remainder of the specificati on and the terms and phrases used in the claims must find clear support or antecedent basis in the description so that the meaning of the terms in the claims may be ascertainable by refe rence to the description.” 37 C.F.R. § 1.75(d)(1). It is therefore entirely appr opriate for a court, when conducting claim construction, to rely heavily on the written description for guidance as to the meaning of the claims.03-1269, -1286 17 3 In addition to consulting the specification, we have held that a court “should also consider the patent’s prosecution hi story, if it is in evidence.” Markman , 52 F.3d at 980; see also Graham v. John Deere Co. , 383 U.S. 1, 33 (1966) (“[A] n invention is construed not only in the light of the claims, but also with reference to the file wrapper or prosecution history in the Pa tent Office.”). The prosecut ion history, which we have designated as part of the “intrinsic evidence,” consists of the complete record of the proceedings before the PTO and in cludes the prior art cited during the examination of the patent. Autogiro , 384 F.2d at 399. Like the specif ication, the prosecution history provides evidence of how the PTO and the inventor understood the patent. See Lemelson v. Gen. Mills, Inc. , 968 F.2d 1202, 1206 (Fed. Cir. 1992). Furthermore, like the specification, the prosec ution history was created by t he patentee in attempting to explain and obtain the patent. Yet because the prosecution hist ory represents an ongoing negotiation between the PTO and the applic ant, rather than the final product of that negotiation, it oft en lacks the clarity of the specific ation and thus is less useful for claim construction purposes. See Inverness Med. Switz. Gm bH v. Warner Lambert Co. , 309 F.3d 1373, 1380-82 (Fed. Cir. 2002) (the ambigui ty of the prosec ution history made it less relevant to claim construction); Athletic Alternatives, Inc. v. Prince Mfg., Inc. , 73 F.3d 1573, 1580 (Fed. Cir. 1996) (the ambiguity of the prosecution history made it “unhelpful as an interpretive resource” fo r claim construction). Nonetheless, the prosecution history can often inform the meaning of the claim language by demonstrating how the inventor understood the invention and whether the inventor limited the invention in the c ourse of prosecution, making the claim scope narrower than03-1269, -1286 18 it would otherwise be. Vitronics , 90 F.3d at 1582-83; see also Chimie v. PPG Indus., Inc. , 402 F.3d 1371, 1384 (Fed. Cir. 2005) (“The purpose of consulting the prosecution history in construing a claim is to ‘exclude any interpretation that was disclaimed during prosecution.’”), quoting ZMI Corp. v. Cardiac Resuscitator Corp. , 844 F.2d 1576, 1580 (Fed. Cir. 1988); Southwall Techs., Inc. v. Cardinal IG Co. , 54 F.3d 1570, 1576 (Fed. Cir. 1995). C Although we have emphasized the importanc e of intrinsic evidence in claim construction, we have also author ized district courts to rely on extrinsic evidence, which “consists of all evidence external to the pat ent and prosecution history, including expert and inventor testimony, dictionar ies, and learned treatises.” Markman , 52 F.3d at 980, citing Seymour v. Osborne , 78 U.S. (11 Wall. ) 516, 546 (1870); see also Vitronics , 90 F.3d at 1583. However, while extrinsic evi dence “can shed useful light on the relevant art,” we have explained that it is “less signifi cant than the intrinsic record in determining ‘the legally operative meani ng of claim language.’” C.R. Bard, Inc. v. U.S. Surgical Corp. , 388 F.3d 858, 862 (Fed. Cir. 2004), quoting Vanderlande Indus. Nederland BV v. Int’l Trade Comm’n , 366 F.3d 1311, 1318 (Fed. Cir. 2004); see also Astrazeneca AB v. Mutual Pharm. Co. , 384 F.3d 1333, 1337 (Fed. Cir. 2004). Within the class of extrinsic evidence, the court has observed that dictionaries and treatises can be useful in claim construction. See Renishaw , 158 F.3d at 1250; Rexnord , 274 F.3d at 1344. We have especially noted the help that technical dictionaries may provide to a court “to better understand the underlying technology” and the way in which one of skill in t he art might use the claim terms. Vitronics , 90 F.3d at03-1269, -1286 19 1584 n.6. Because dictionaries, and especially technical dictionaries, endeavor to collect the accepted meanings of terms used in various fields of science and technology, those resources have been properly recognized as among the many tools that can assist the court in determining the meaning of particular terminology to those of skill in the art of the invention. See Teleflex, Inc. v. Fi cosa N. Am. Corp. , 299 F.3d 1313, 1325 (Fed. Cir. 2002). Such evidence, we have held, may be considered if the court deems it helpful in determining “t he true meaning of language used in the patent claims.” Markman , 52 F.3d at 980. We have also held that extrinsic evidence in the form of expert testimony can be useful to a court for a variety of purpos es, such as to provide background on the technology at issue, to explain how an inv ention works, to ensur e that the court’s understanding of the technical aspects of the pat ent is consistent wit h that of a person of skill in the art, or to estab lish that a particular term in the patent or the prior art has a particular meaning in the pertinent field. See Pitney Bowes, Inc. v. Hewlett-Packard Co. , 182 F.3d 1298, 1308-09 (Fed. Cir. 1999); Key Pharms. v. Hercon Labs. Corp. , 161 F.3d 709, 716 (Fed. Cir. 1998). However, conclusory, unsupported assertions by experts as to the definition of a claim term are not useful to a court. Similarly, a court should discount any expert testim ony “that is clearly at odds with the claim construction mandated by the claims themselves, the wr itten description, and the prosecution history, in other words, with the written record of the patent.” Key Pharms. , 161 F.3d at
716. We have viewed extrinsic evidence in general as less reliable than the patent and its prosecution history in determining how to read claim terms, for several reasons.03-1269, -1286 20 First, extrinsic evidence by definition is not part of the patent and does not have the specification’s virtue of being created at the time of patent prosecution for the purpose of explaining the patent’s sc ope and meaning. Second, while claims are construed as they would be understood by a hypothetical person of skill in the art, extrinsic publications may not be written by or for skilled artisans and therefore may not reflect the understanding of a skilled artisan in the fiel d of the patent. Thir d, extrinsic evidence consisting of expert reports and testimony is generated at the time of and for the purpose of litigation and thus can suffer from bias that is not pr esent in intrinsic evidence. The effect of that bias can be exacerbated if the expert is not one of skill in the relevant art or if the expert’s opinion is o ffered in a form that is not subject to crossexamination. See Senmed, Inc. v. Richard- Allan Med. Indus., Inc. , 888 F.2d 815, 819 n.8 (Fed. Cir. 1989). Fourth, there is a virtually unbounded universe of potential extrinsic evidence of some ma rginal relevance that could be brought to bear on any claim construction question. In the course of litigation, each party will naturally choose the pieces of extrinsic evidence most favor able to its cause, leav ing the court with the considerable task of filtering the useful extrinsic evidence from the fluff. See Daubert v. Merrell Dow Pharms., Inc. , 509 U.S. 579, 595 (1993) (“Expert evidence can be both powerful and quite misleading because of the diffi culty in evaluating it.”). Finally, undue reliance on extrinsic evidence poses the ri sk that it will be used to change the meaning of claims in derogation of the “indisputable public records consisting of the claims, the specification and the prosecution histor y,” thereby undermining the public notice function of patents. Southwall Techs. , 54 F.3d at 1578.03-1269, -1286 21 In sum, extrinsic evidence may be useful to the court, but it is unlikely to result in a reliable interpretation of patent claim scope unless considered in the context of the intrinsic evidence. Nonetheless, because ex trinsic evidence can help educate the court regarding the field of the invention and can help the cour t determine what a person of ordinary skill in the art would understand claim terms to mean, it is permissible for the district court in its sound discr etion to admit and use such evidence. In exercising that discretion, and in weighing all the evidenc e bearing on claim construction, the court should keep in mind the flaws inherent in each type of evidence and assess that evidence accordingly.
III Although the principles outlined above have been articulated on numerous occasions, some of this court’s cases hav e suggested a somewhat different approach to claim construction, in which the court has given greater emphasis to dictionary definitions of claim terms and has assigned a less prominent role to the specification and the prosecution history. T he leading case in this line is Texas Digital Systems, Inc. v. Telegenix, Inc. , 308 F.3d 1193 (Fed. Cir. 2002).
A
In Texas Digital , the court noted that “dictionar ies, encyclopedias and treatises are particularly useful resources to assist the court in determining the ordinary and customary meanings of claim terms.” 308 F.3d at 1202. Those texts, the court explained, are “objective resources that serv e as reliable sources of information on the established meanings that would have been attr ibuted to the terms of the claims by those of skill in the art,” and they “deserve no less fealty in the context of claim03-1269, -1286 22 construction” than in any other area of law. Id. at 1203. The court added that because words often have multiple dictionary meanings, the intrinsic record must be consulted to determine which of the different possible di ctionary meanings is most consistent with the use of the term in question by the inventor . If more than one dict ionary definition is consistent with the use of the words in the intrinsic re cord, the court stated, “the claim terms may be construed to encompass all such consistent meanings.” Id. The Texas Digital court further explained that the patent’s specification and prosecution history must be consulted to determine if the patentee has used “the words [of the claim] in a manner clearly inconsist ent with the ordinary m eaning reflected, for example, in a dictionary definition.” 308 F.3d at 1204. The court identified two circumstances in which such an inconsist ency may be found. Firs t, the court stated, “the presumption in favor of a dictionary def inition will be overcome where the patentee, acting as his or her own lexicographer, has clear ly set forth an explicit definition of the term different from its ordinary meaning.” Id. Second, “the pres umption also will be rebutted if the inventor has disavowed or disclaimed scope of coverage, by using words or expressions of manifest ex clusion or restriction, repr esenting a clear disavowal of claim scope.” Id. The Texas Digital court explained that it advanc ed the methodology set forth in that opinion in an effort to combat what this court has termed “one of the cardinal sins of patent law—reading a lim itation from the written de scription into the claims,” SciMed Life Sys. , 242 F.3d at 1340. The court concluded t hat it is improper to consult “the written description and prosecution history as a threshold step in the claim construction process, before any effort is made to discern the ordi nary and customary meanings03-1269, -1286 23 attributed to the words themselves.” Texas Digital , 308 F.3d at 1204. To do so, the court reasoned, “invites a violation of our precedent counseling against importing limitations into the claims.” Id. Summarizing its analysis, the Texas Digital court stated: By examining relevant dictionarie s, encyclopedias, and treatises to ascertain possible meanings that w ould have been attributed to the words of the claims by those skilled in the art, and by further utilizing the intrinsic record to select from those possi ble meanings the one or ones most consistent with the use of the words by the inventor , the full breadth of the limitations intended by the inventor will be more accurately determined and the improper importation of unint ended limitations from the written description into the claims will be more easily avoided. Id. at 1205. B Although the concern expre ssed by the court in Texas Digital was valid, the methodology it adopted placed too much re liance on extrinsic sources such as dictionaries, treatises, and encyclopedias and too li ttle on intrinsic sources, in particular the specification and prosecuti on history. While the court noted that the specification must be consulted in every case, it suggest ed a methodology for clai m interpretation in which the specification shoul d be consulted only after a det ermination is made, whether based on a dictionary, treatise, or other source, as to the ordinary meaning or meanings of the claim term in dispute. Even then, re course to the specification is limited to determining whether the spec ification excludes one of t he meanings derived from the dictionary, whether the presumpt ion in favor of the dictionar y definition of the claim term has been overcome by “an exp licit definition of the term different from its ordinary meaning,” or whether the invent or “has disavowed or discl aimed scope of coverage, by using words or expressions of manifest exclusion or rest riction, representing a clear disavowal of claim scope.” 308 F.3d at 1204. In effect, the Texas Digital approach03-1269, -1286 24 limits the role of the specif ication in claim construction to serving as a check on the dictionary meaning of a claim term if the specification requires the court to conclude that fewer than all the dictionary definitions apply, or if t he specification contains a sufficiently specific alternativ e definition or disavowal. See, e.g. , Texas Digital , 308 F.3d at 1202 (“unless compelled otherwise, a court will give a claim term the full range of its ordinary meaning”); Nystrom v. TREX Co. , 374 F.3d 1105, 1111-13 (Fed. Cir. 2004) (ascertaining the “full range” of the ordinary meaning of the term “board” through a collection of dictionary definit ions, and stating that those c andidate definitions should be removed from consideration only if they were “disclaimed” in the written description or prosecution history); Inverness Med. Switz. , 309 F.3d at 1379 (claim should be construed to encompass multiple dictionary meanings unless “the specification or prosecution history clearly demonstrates that only one of the multiple meanings was intended”). That approach, in our view, improper ly restricts the role of the specification in claim construction. Assigning such a limited role to the specif ication, and in particular requiring that any definition of claim language in the specification be express, is inconsistent with our rulings that the specificati on is “the single best guide to the meaning of a disputed term,” and that the specification “act s as a dictionary when it expr essly defines terms used in the claims or when it defines terms by implication.” Vitronics , 90 F.3d at 1582; Irdeto Access, Inc. v. Echostar Satellite Corp. , 383 F.3d 1295, 1300 (Fed. Cir. 2004) (“Even when guidance is not provided in explicit defin itional format, the specification may define claim terms by implication such that the meaning may be found in or ascertained by a reading of the patent documents.”) (citations omitted); Novartis Pharms. Corp. v. Abbott03-1269, -1286 25 Labs. , 375 F.3d 1328, 1334-35 (Fed. Cir. 2004) (same); Bell Atl. Network Servs., Inc. v. Covad Communications Group, Inc. , 262 F.3d 1258, 1268 (Fed. Cir. 2001) (“[A] claim term may be clearly redefined without an explic it statement of redefinition.”). The main problem with elevat ing the dictionary to such prominence is that it focuses the inquiry on the abstract meaning of words rather than on the meaning of claim terms within the context of the patent. Properly viewed, the “ordinary meaning” of a claim term is its meaning to the ordinary artisan after reading the entire patent. Yet heavy reliance on the dictionary divorced from the intrinsic evidence risks transforming the meaning of the claim term to the artisan into the meaning of the term in the abstract, out of its particular context, which is the specification. The patent system is based on the proposition that claims cover only the invented subject matter. As the Supreme Court has stated, “[i]t seems to us that nothing can be more just and fair, both to the patentee and the public, than that the former should understand, and correctly describe, just what he has invented, and fo r what he claims a patent.” Merrill v. Yeomans , 94 U.S. at 573-74. The use of a dictionary definition can conflict with that directive because the patent applicant did not create the dictionary to describe the invention. Thus, there may be a disconnect between the patentee’s responsibility to describe and claim his invention, and the dictionary edi tors’ objective of aggregating all possible definitions for particular words. Although the Texas Digital line of cases permit the dictionary definition to be narrowed in some circumstances even when t here is not an explicit disclaimer or redefinition in the specificat ion, too often that line of cases has been improperly relied upon to condone the adoption of a dictionary definition entirely divorced from the03-1269, -1286 26 context of the written description. The problem is t hat if the district court starts with the broad dictionary definition in every case and fails to fully appreciate how the specification implicit ly limits that definit ion, the error will systematically cause the construction of the claim to be unduly expansive. The risk of systematic overbreadth is greatly reduced if the court instead focuses at the outset on how the patentee used the claim term in the claims, specification, and pr osecution history, ra ther than starting with a broad definition and whittling it down. Dictionaries, by their nature, provide an expansive array of definitions. General dictionaries, in particular, strive to collect all uses of particular words, from the common to the obscure. By design, general dictionarie s collect the definitions of a term as used not only in a particular art field, but in many different settings. In such circumstances, it is inevitable that the multiple dictionar y definitions for a term will extend beyond the “construction of the patent [that] is conf irmed by the avowed understanding of the patentee, expressed by him, or on his behalf, when his applicat ion for the original patent was pending.” Goodyear Dental Vulcanite Co. v. Davis , 102 U.S. 222, 227 (1880). Thus, the use of the dict ionary may extend patent prot ection beyond what should properly be afforded by t he inventor’s patent. See Smith v. Snow , 294 U.S. 1, 14 (1935) (“if the claim were fairly susceptible of two constructions, that should be adopted which will secure to the patentee his actual invention ”) (emphasis added). For that reason, we have stated that “a general-usage dictionary c annot overcome art-specific evidence of the meaning” of a claim term. Vanderlande Indus. Nederland , 366 F.3d at 1321; see also Renishaw , 158 F.3d at 1250, quoting Liebscher v. Boothroyd , 258 F.2d 948, 951 (CCPA 1958) (“Indiscriminate reliance on defin itions found in dictionaries can often03-1269, -1286 27 produce absurd results. . . . One need not arbitrarily pick and choose from the various accepted definitions of a word to decide which meaning was intended as the word is used in a given claim. The subject matter, the context, etc., will more often than not lead to the correct conclusion.”). Even technical dictionaries or treatises, under certain circumstances, may suffer from some of these deficienc ies. There is no guarantee that a term is used in the same way in a treatise as it w ould be by the patentee. In fact, discrepancies between the patent and treatises are apt to be common because the patent by its nature describes something novel. See Autogiro , 384 F.2d at 397 (“Often the invention is novel and words do not exist to describe it. The dictionary does not always keep abreast of the inventor. It cannot.”). Moreover, different dictionaries may contain somewhat different sets of definitions for the same words. A clai m should not rise or fall based upon the preferences of a particular dictionary editor, or the court’s independent decision, uninformed by the specificati on, to rely on one dictionary ra ther than another. Finally, the authors of dictionaries or treatises may simplify ideas to communicate them most effectively to the public and may thus choos e a meaning that is not pertinent to the understanding of particular claim language. See generally Ellen P. Aprill, The Law of the Word: Dictionary Shopping in the Supreme Court , 30 Ariz. St. L.J. 275, 293-314 (1998). The resulting definiti ons therefore do not necessarily reflect the inventor’s goal of distinctly setting forth his invention as a person of ordinary skill in that particular art would understand it.03-1269, -1286 28 As we have noted above, however, we do not intend to preclude the appropriate use of dictionaries. Dictionar ies or comparable sources are often useful to assist in understanding the commonly understood meani ng of words and have been used both by our court and the Supreme Cour t in claim interpretation. See Exhibit Supply Co. v. Ace Patents Corp. , 315 U.S. 126, 134 (1942) (relying on dictionaries to construe the claim term “embedded”); Weber Elec. Co. v. E.H. Freeman Elec. Co. , 256 U.S. 668, 678 (1921) (approving circuit court’s use of dict ionary definitions to define claim terms); Renishaw , 158 F.3d at 1247-53 (approvi ng the use of dictionaries with proper respect for the role of intrinsic evidence). A di ctionary definition has the value of being an unbiased source “accessible to the pub lic in advance of litigation.” Vitronics , 90 F.3d at 1585. As we said in Vitronics , judges are free to consult dictionaries and technical treatises at any time in order to better understand the underlying technology and may also rely on dictionary definiti ons when construing claim terms, so long as the dictionary definition does c ontradict any definition found in or ascertained by a reading of the patent documents. Id. at 1584 n.6. We also acknowledge that the purpose underlying the Texas Digital line of cases—to avoid the danger of r eading limitations from the s pecification into the claim— is sound. Moreover, we recogni ze that the distinction betw een using the specification to interpret the meaning of a claim and importing lim itations from the sp ecification into the claim can be a difficult one to apply in practice. See Comark Communications, Inc. v. Harris Corp. , 156 F.3d 1182, 1186-87 (Fed. Cir. 1998) (“there is sometimes a fine line between reading a claim in light of the spec ification, and reading a limitation into the claim from the specification”). Howe ver, the line between construing terms and03-1269, -1286 29 importing limitations can be discerned with reasonable certai nty and predictability if the court’s focus remains on understanding how a per son of ordinary skill in the art would understand the claim terms. For instance, al though the specificati on often describes very specific embodiments of the inv ention, we have repeatedly warned against confining the claims to those embodiments. See, e.g. , Nazomi Communications, Inc. v. ARM Holdings, PLC , 403 F.3d 1364, 1369 (Fed. Cir. 2005) (claims may embrace “different subject matter than is illustra ted in the specific embodiments in the specification”); Liebel-Flarsheim , 358 F.3d at 906-08; Teleflex , 299 F.3d at 1327; SRI Int’l v. Matsushita Elec. Corp. of Am. , 775 F.2d 1107, 1121 (Fed. Cir. 1985). In particular, we have expressly rejected the c ontention that if a patent describes only a single embodiment, the claims of the patent must be construe d as being limited to that embodiment. Gemstar-TV Guide , 383 F.3d at 1366. That is not just because section 112 of the Patent Act requires that the claims themselves set forth the limits of the patent grant, but also because per sons of ordinary skill in the art rarely would confine their definitions of terms to the exact r epresentations depicted in the embodiments. To avoid importing limitations from the specification into the claims, it is important to keep in mind that the purposes of the specification are to te ach and enable those of skill in the art to make and use the invent ion and to provide a best mode for doing so. See Spectra-Physics, Inc. v. Coherent, Inc. , 827 F.2d 1524, 1533 (Fed. Cir. 1987). One of the best ways to teach a person of ordinar y skill in the art how to make and use the invention is to provide an example of how to pr actice the invention in a particular case. Much of the time, upon reading the specification in that context, it will become clear whether the patentee is setting out specific examples of the invention to accomplish03-1269, -1286 30 those goals, or whether the patentee instead intends for the claims and the embodiments in the specification to be strictly coextensive. See SciMed Life Sys. , 242 F.3d at 1341. The manner in which the patentee us es a term within the specification and claims usually will make the distinction apparent. See Snow v. Lake Shore & M.S. Ry. Co. , 121 U.S. 617, 630 (1887) (it was clear from the specification that there was “nothing in the context to indicate that the patentee contemplated any alternative” embodiment to the one presented). In the end, there will still remain some ca ses in which it will be hard to determine whether a person of skill in the art woul d understand the embodiments to define the outer limits of the claim term or merely to be exemplary in nature. While that task may present difficulties in some cases, we nonet heless believe that attempting to resolve that problem in the context of the particular patent is likel y to capture the scope of the actual invention more accurately than either strictly limiting the sc ope of the claims to the embodiments disclosed in t he specification or divorci ng the claim language from the specification.
In Vitronics , this court grappled with the same problem and set forth guidelines for reaching the correct claim constructi on and not imposing impr oper limitations on claims. 90 F.3d at 1582. The underlying goal of our decision in Vitronics was to increase the likelihood that a court will comprehend how a person of ordinary skill in the art would understand the claim terms. See id. at 1584. In that pr ocess, we recognized that there is no magic formula or catechis m for conducting claim construction. Nor is the court barred from considering any particu lar sources or required to analyze sources in any specific sequence, as long as those sources are not used to contradict claim03-1269, -1286 31 meaning that is unambiguous in light of the intrinsic evidence. See id. at 1583-84; Intel Corp. v. VIA Techs., Inc. , 319 F.3d 1357, 1367 (Fed. Cir. 2003) . For example, a judge who encounters a claim term while reading a pat ent might consult a general purpose or specialized dictionary to begin to understand t he meaning of the term, before reviewing the remainder of the patent to determine how the patentee has used the term. The sequence of steps used by the judge in cons ulting various sources is not important; what matters is for the cour t to attach the appropriate weight to be assigned to those sources in light of the statutes and policies that inform patent law. Vitronics , 90 F.3d at 1582. In Vitronics , we did not attempt to provide a ri gid algorithm for claim construction, but simply attempted to explain why, in general, certain types of evidence are more valuable than others. Today, we adhere to that approach and reaffirm the approach to claim construction outlined in that case, in Markman , and in Innova . We now turn to the application of those principles to the case at bar.
IV
A The critical language of claim 1 of the ’798 patent—“further means disposed inside the shell for increasing its load bearing capacity comprising internal steel baffles extending inwardly from the steel shell wa lls”—imposes three cl ear requirements with respect to the baffles. First, the baffles mu st be made of steel. Second, they must be part of the load-bearing means for the wall section. Third, th ey must be pointed inward from the walls. Both parties, stipulating to a dictionary definition, also conceded that the term “baffles” refers to objects that check, impede, or obstruct the flow of something.03-1269, -1286 32 The intrinsic evidence confirms that a person of skill in the art would understand that the term “baffles,” as used in the ’798 patent, would have that generic meaning. The other claims of the ’798 patent s pecify particular functions to be served by the baffles. For example, dependent claim 2 states that the baffles may be “oriented with the panel sections disposed at angles for def lecting projectiles su ch as bullets able to penetrate the steel plates.” The inclusi on of such a specific limitation on the term “baffles” in claim 2 makes it likely that the patentee did not cont emplate that the term “baffles” already contai ned that limitation. See Dow Chem. Co. v. United States , 226 F.3d 1334, 1341-42 (Fed. Cir. 2000) (concluding that an independent claim should be given broader scope than a dependent claim to avoid rendering the dependent claim redundant). Independent claim 17 fu rther supports that proposit ion. It states that baffles are placed “projecting inwardly from the outer shell at angl es tending to deflect projectiles that penetrate the outer shell.” That limitat ion would be unnecessary if persons of skill in the art under stood that the baffles inherently served such a function. See TurboCare , 264 F.3d at 1123 (claim terms should not be read to contain a limitation “where another claim restricts the invention in exactly the [same] manner”). Dependent claim 6 provides an additional requirement for the baffles, stating t hat “the internal baffles of both outer panel sect ions overlap and interlock at angles providing deflector panels extending from one end of the module to the other.” If the baffles recited in claim 1 were inherently placed at specific angles , or interlocked to form an intermediate barrier, claim 6 would be redundant. The specification further supports the c onclusion that persons of ordinary skill in the art would understand the baffl es recited in the ’798 patent to be load-bearing objects03-1269, -1286 33 that serve to check, impede, or obstruct flow. At several points, the specification discusses positioning the baffles so as to deflect projectiles. See ’798 patent, col. 2, ll. 13-15; id. , col. 5, ll. 17-19. The patent states that one advant age of the invention over the prior art is that “[t]her e have not been effective ways of dealing with these powerful impact weapons with inexpensive housing.” Id. , col. 3, ll. 28-30. While that statement makes clear the invention envisions baffles t hat serve that functi on, it does not imply that in order to qualify as baffles within t he meaning of the claims, the internal support structures must serve the proj ectile-deflecting function in a ll the embodiments of all the claims. The specification must teach and enable all the claims, and the section of the written description discussing t he use of baffles to deflect projectiles serves that purpose for claims 2, 6, 17, and 23, which specifically claim baffles that deflect projectiles. See In re Wright , 999 F.2d 1557, 1561 (Fed. Cir. 1993). The specification discusses several other purposes served by the baffles. For example, the baffles are described as provid ing structural suppor t. The patent states that one way to increase load-bearing capacity is to use “at least in part inwardly directed steel baffles 15, 16.” ’798 patent, col. 4, ll. 14-15. The baffle 16 is described as a “strengthening triangular baffle.” Id. , col. 4, line 37. Im portantly, Figures 4 and 6 do not show the baffles as par t of an “intermediate interlocking, but not solid, internal barrier.” In those figures, the baffle 16 simply provides structural support for one of the walls, as depicted below:Other uses for the baffles are listed in the specification as well. In Figure 7, the overlapping flanges “provide for overlapping and interlocking the baffles to produce substantially an intermediate barrier wa ll between the opposite [wall] faces”:

’798 patent, col. 5, ll. 26-29. Those baffles thus create small compartments that can be filled with either sound and therma l insulation or rock and gravel to stop projectiles. Id. ,

03-1269, -1286 3403-1269, -1286 35 col. 5, ll. 29-34. By s eparating the interwall area in to compartments (see, e.g., compartment 55 in Figure 7), the user of the modules can choose different types of material for each compartment, so that the module can be “easily custom tailored for the specific needs of each installation.” Id. , col. 5, ll. 36-37. When material is placed into the wall during installation, the baffles obs truct the flow of material from one compartment to another so that this “custom tailoring” is possible. The fact that the written description of the ’798 patent sets forth multiple objectives to be served by the baffles recit ed in the claims confirms that the term “baffles” should not be read restrictively to requi re that the baffles in each case serve all of the recited functions. We have held that “[t]he fact that a patent asserts that an invention achieves several objectives does not require that each of the claims be construed as limited to structur es that are capable of achiev ing all of the objectives.” Liebel-Flarsheim , 358 F.3d at 908; see also Resonate Inc. v. Alteon Websystems, Inc. , 338 F.3d 1360, 1367 (Fed. Cir. 2003). Although def lecting projectile s is one of the advantages of the baffles of t he ’798 patent, the patent does not require that the inward extending structures always be capable of performing that function. Accordingly, we conclude that a person of skill in the art woul d not interpret the disclosure and claims of the ’798 patent to mean that a structure extending inward from one of the wall faces is a “baffle” if it is at an acute or obtuse angle, but is not a “ba ffle” if it is disposed at a right angle.
B Invoking the principle that “claims shoul d be so construed, if possible, as to sustain their validity,” Rhine v. Casio, Inc. , 183 F.3d 1342, 1345 (F ed Cir. 1999), AWH03-1269, -1286 36 argues that the term “baffles ” should be given a restrictive meaning because if the term is not construed restrictively, the asserted claims would be invalid. While we have acknowledged the maxim that claims should be construed to preserve their validity, we have not applied that principle broadly, and we have certainly not endorsed a regime in wh ich validity analysis is a regular component of claim construction. See Nazomi Communications , 403 F.3d at 1368-69. Instead, we have limited the maxim to cases in which “the cour t concludes, after applying all the available tools of claim construction, that the claim is still ambiguous.” Liebel-Flarsheim , 358 F.3d at 911; see also Generation II Orthonics Inc. v. Med. Tech. Inc. , 263 F.3d 1356, 1365 (Fed. Cir. 2001) (“[C]laims can only be constr ued to preserve thei r validity where the proposed claim construction is ‘practicabl e,’ is based on sound claim construction principles, and does not revise or ignore the explicit language of the claims.”); Elekta Instrument S.A. v. O.U.R . Scientific Int’l, Inc. , 214 F.3d 1302, 1309 (Fed. Cir. 2000) (“having concluded that the amended claim is susceptible of only one reasonable construction, we cannot construe the claim differently from its plain meaning in order to preserve its validity”); E.I. du Pont de Nemours & Co . v. Phillips Petroleum Co. , 849 F.2d 1430, 1434 (Fed. Cir. 1988) (re jecting argument that limit ations should be added to claims to preserve the validity of the claims). In such cases, we have looked to whether it is reasonable to infer that the PTO w ould not have issued an invalid patent, and that the ambiguity in the claim language should t herefore be resolved in a manner that would preserve the patent’s validity. That is the rationale that gave rise to the maxim in the first place. In Klein v. Russell , 86 U.S. (19 Wall.) 433, 466 (1873), the owner of a reissued patent argued for a03-1269, -1286 37 narrow construction of the patent, while t he accused infringer argued for a broader construction. The Court noted that the law “required that the reissue should be for the same invention as t he original patent.” Id. Because the reissue, which was granted under the predecessor to 35 U.S.C. § 251, would have been improper under the broader construction, the Court “presumed the Commissioner did his duty” and did not issue an invalid patent. For that reas on, among others, the Court construed the disputed claim language in a manner that “sus tain[ed] the patent and the construction claimed by the patentee,” si nce that “can be done consist ently with the language which he has employed.” Id. The applicability of the doctrine in a particular case therefore depends on the strength of the in ference that the PTO woul d have recognized that one claim interpretation would render the clai m invalid, and that the PTO would not have issued the patent assuming that to be the proper construction of the term. In this case, unlike in Klein and other cases in which the doctrine of construing claims to preserve their validity has been invoked, the claim term at issue is not ambiguous. Thus, it can be construed wit hout the need to consider whether one possible construction would render the claim invalid while the other would not. The doctrine of construing claims to preserve their validity, a doctrine of limited utility in any event, therefore has no applicability here. In sum, we reject AWH’s arguments in favo r of a restrictive def inition of the term “baffles.” Because we disagr ee with the district court’s claim construction, we reverse the summary judgment of noninfringement. In light of our decision on claim construction, it is necessary to remand the in fringement claims to the district court for further proceedings.03-1269, -1286 38 V With respect to Mr. Phillips’s allegation of misappropriation of trade secrets, we agree with the panel’s decision upholding the dist rict court’s ruling on that issue, in which the district court di smissed the trade secret clai m on statute of limitations grounds. See Phillips , 363 F.3d at 1214-1216. Accordi ngly, based on the panel’s disposition of that issue, we affirm the district court’s dismi ssal of the trade secret claim. With respect to AWH’s cross-appeal, we also agree with the pane l’s reasoning and its conclusion that the cr oss-appeal is improper. See id. at 1216. We therefore dismiss the cross-appeal.
VI In our order granting r ehearing en banc, we asked the parties to brief various questions, including the following: “ Consistent with the Supr eme Court’s decision in Markman v. Westview Instruments , 517 U.S. 370 (1996), and our en banc decision in Cybor Corp. v. FAS Technologies, Inc. , 138 F.3d 1448 (Fed. Cir. 1998) , is it appropriate for this court to accord any deference to any aspect of trial court claim construction rulings? If so, on what aspects, in what circumstances, and to what extent?” After consideration of the matter, we have decided not to address that issue at this time. We therefore leave undisturbed our prior en banc decision in Cybor

. Each party shall bear its own costs for this appeal.

AFFIRMED IN PART, REVERSED IN PAR T, DISMISSED IN PART, and REMANDED.

## United States Court of Appeals for the Federal Circuit

03-1269,-1286

EDWARD H. PHILLIPS, Plaintiff-Appellant,

v. AWH CORPORATION, HOPEMAN BROTHERS, INC., and LOFTON CORPORATION, Defendants-Cross Appellants.

LOURIE, Circuit Judge , concurring in part and dissenti ng in part, with whom NEWMAN, Circuit Judge , joins.

I fully join the portion of the court's opinion resolving the relative weights of specification and dictionaries in interpreting patent claims, in fa vor of the specification. I could elaborate more expansively on that t opic, but Judge Bryson's opinion for the majority says it so well, there is little reason for me to repeat its truths. I also agree with the court that claims need not necessarily be limited to specific or preferred embodiments in the specificati on, although they are limited to what is contained in the overall disclosure of the specification. However, I do dissent from the court's decision to reverse and remand the district court's decision. The original panel decision of this court, which implicitly decided the case based on the priorities that the en banc court has now reaffirmed, interpreted the claims in light of the spec ification and found that the defendant did not infringe theclaims. We affirmed the district court, whic h had arriv ed at a similar conclusion. Th e dissent from the panel decis ion relied on the "d ictionaries first" procedure, which the court now has decided not to follow. Thus, while the claim construction issue had to be decided by the en banc court, I see no reason for t he court, having reaffirmed the principle on which the district judge and the panel originally dec ided t he case, to send it back for further review. The court premises its reverse-and-re mand decision on the concept of claim differentiation and the r easoning that the contested term " baffle" need not fulfill all of t he functions set out for i t in the specificat ion. Reasonable people can differ on thos e points. However, the court did not take this case en banc because the full c o urt differed with the panel majority on thos e dis putable cr iteria. It did s o to resolve the claim construction issue, which it has now done so well. Having done so, I believ e that it should sim p ly affirm the district court's dec ision on the merits, consistently with that court's rationale and that of the panel that affirmed the di stric t court, which it now adopts.
I will n o t critique in d e tail particu la r stat ements the majority makes in rationalizing its reversal of the district court's decision, su ch as "that a person of skill in the art would not interpret the disc losure and claims of the '798 patent to mean that a structure extending inward from one of t he wall fac e s is a ' b affle' if it is at an ac ute or obtus e angle, but is not a 'baffle' if it is disposed at a right angle," or t hat "the patent does not require that the inward ex tending structures always be capable of performing that function [deflecting projec tiles]" in order to be consider ed 'baffles'.

03-1269,-1286 2I will s i mply point out that the s pecificati on contains no disc losur e of baffles at right angles. Moreover, as t he majority correctly states , a patent specification is intended to describe one's inventi on, and it is essential to r ead a specification in order to interpret the meaning of the claims. This s pecification makes clear that the "baffles" in this invention are angled. There is no refer ence to baffles that show them to be other than angled. The abstract refers to "bullet def lecting . . . baffles." Only angled baffle s can deflect. It then mentions "internal baffles at angles for deflecting bullets." That could not be clearer. The specification t hen refers several times to baffles, often to figures in the drawings, all of which are to angled baffles. A compelling point is that the only numbered references to baffl es (15, 16, 26, 27, 30, and 31) all show angled baffles. The spec ification further states that st eel panels "f orm the internal baffles at angles for deflecting bullets." It states that the baffles are "dispos ed at such angles that bullets which might penetrate the outer steel panels are deflected." It explains that if bullets "were to penetrate the outer steel wall, the baffles are dis posed at a n gles whic h tend to deflect the bullets." There is no specific reference in this patent to a baffle that is not angled at other than 90o. While, as the majority states, the specific ation indicat e s that multiple objec tives are achiev ed by the invention, none of t he other objectives is dependent upon whether the baffles are at other than a 90o angle, w hereas the constantly stated objective of deflection of bullets is dependent upon such an angle. Finally, ev en though claim cons truction is a question of law, reviewable by this court without formal deference, I do believ e that we ought to lean toward affirmance of a claim const r uction in t he absenc e of a strong conviction of error. I do not have such a

03-1269,-1286 3conviction in this case, after considering the district court's opinion and t he patent specification. For these reasons, while I wholeheartedl y join t h e majority opin i on in its discussion and resolut i on of the "specification v. dictionaries" issue, I would affirm the decision below.

03-1269,-1286 4

## United States Court of Appeals for the Federal Circuit

03-1269, -1286

EDWARD H. PHILLIPS, Plaintiff-Appellant,

v. AWH CORPORATION, HOPEMAN BROTHERS, INC., and LOFTON CORPORATION, Defendants-Cross Appellants.

MAYER, Circuit Judge , with whom NEWMAN, Circuit Judge , joins, dissenting. Now more than ever I am convinced of the futility, indeed the absurdity, of this court’s persistence in adhering to the falsehood that claim construction is a matter of law devoid of any factual component. Bec ause any attempt to fashion a coherent standard under this regime is point less, as illustrated by our many failed attempts to do so, I dissent. This court was created for the purpose of bringing consist ency to the patent field. See H.R. Rep. No. 312, 97th Cong., 1st Sess. 20-23 (1981). Instead, we have taken this noble mandate, to reinvigorate the patent and introduce predictability to the field, and focused inappropriate power in this cour t. In our quest to elevate our importance, we have, however, disregarded our role as an appellate court; t he resulting mayhem has seriously undermined the legitimacy of the process, if not the integrity of the institution.In the name of unifor m ity, Cybor Corp. v. F AS Tec hnologies, Inc. , 138 F.3d 1448 (Fed. Cir. 1998) (en banc), held that claim cons tructi on does not involve subsidiary or underlying questions of fact and t hat we are, therefore, unbri dled by either the expertise or efforts of the district court. 1 What we hav e wrought, instead, is the substitution of a black box, as it so pejorativel y has been said of the jury, with t he black hole of this court. Out of this void we emit “legal” pronouncem ents by way of “int erpretive necromancy” 2 ; these rulings resemble reality, if at all, onl y by chance. Regardless, and wit h a blind eye to the cons equences, we continue to struggl e under this irrational and reckless regime, trying every alternative—dictionaries first, di ctionaries second, never dictionaries, etc., etc., etc. Again today we vainly attempt to est ablish standards by which this court will interpret claims. But after proposing no fewer than seven questions, receiving more than thirty amici curia e briefs, and whipping the bar into a frenzy of expectat i on, we say nothing new, but merely restate what has beco me the practice over the last ten years— that we will decide c a s e s according to what ever mode or method results in the outcome we des ire, or at least allows us a seemingly plaus ible way out of the case. I am not surprised by this. Indeed, there can be no workable s t andards by which this court will interpret claims so long as we are blind t o the factual compon ent of the task. See

1 The Supreme Court did not suggest in affirming Markman v. Westview Instruments, Inc. , 52 F.3d 967 ( 1995) (en banc), that clai m const r uction is a purely leg a l question. 517 U.S. 370 (1996). It held only that, as a policy matter, the judge, as opposed to the jury, should determine t he meaning of a patent claim. See Cybor , 138 F.3d at 1464 (Mayer, C.J., dissenting) (expla ining that “the [Suprem e] Court chose not to accept our formulation of claim construction: as a pure question of law to be decid ed de novo in all cases on appeal”).

2 See The Holmes Group, Inc. v. Vo rnado Air Circulat i on Sys., Inc. , 535 U.S. 826, 833 (2002).
03-1269,-1286 2Cooter & Gell v. Hartmarx Corp. , 496 U.S. 384, 405 (1990) (“Fact-bound resolution s cannot be made unif o rm through appellate revi ew, de novo or otherwise.” (quoting Mars Steel Corp. v. Cont’l Bank N. A. , 880 F.2 d 928, 936 (7th Cir.1989))). 3
Federal Rule of Civil Procedur e 52(a) states that “[f]indings of fact . . . shall not be set as ide unless clearly e rroneous, and due regard shall be given to the opportunity of the trial court to judge of the credibility of witnes ses.” Acc o rding to the Supreme Court, this “[r]ule means what it says”—that findings of fact, even “those described as ‘ultimate facts’ because they may determi ne the outcome of litigation, ” are to be reviewed deferentially on appeal. 4 Bose Corp. v. Consumer s Union of United States ,

3 The question asked but not answer ed by the court which might have allo wed it to cure its self-inflict ed wou n d was: “Question 7. Consistent with the Supreme Court’s decision in Markman v. Westvie w Instrume nts, Inc. , 517 U.S. 370 (1996) and our en banc decisio n in Cybor Corp. v. FAS Technologies, Inc. , 138 F.3d 1448 (Fed. Cir. 1998), is it appr opriate for th is court to accord any deference to any aspect of trial court claim cons truction ru lings? If so, on what aspects, in what circumstances, and to what extent?”

4 Because some facts are so intertwined with a constit u tional standard the Supreme Court has held that de novo review is appropriate. F o r example, whether a defendant has acted with actual malice in a defamation suit is reviewed de nov o because, among other reasons, the scope of the First Amendment is shaped and applied by reference to such factual determinations. Bose , 466 U.S. at 502 (“[T]he content of the rule is not revealed simply by its literal text, but rather is given meaning through the evolutionary process of common- law adjudication.”). Similarly , whether there is reasonable s u spicion to conduct an investigatory stop or probable cause to perform a search under the Fourth Amendm ent are reviewed without deference. Ornelas v. United States , 517 U.S. 690, 696 ( 1996) (holding that the protections afforded by the Fourth Amendm ent are “fluid conc epts that take their substantive content from the parti cular contexts in wh ic h the standards are being asses s ed”). The reasoning behind these lim ited exceptions surely does not app ly to claim c o nstruction. While appearing from the perspec tive of this court’s limited sphere of influence to be dreadfully important, claim c ons truction does not implicate a constitutional value. Cf. Bose , 466 U.S. at 502 (“[T]he c onstitutional values protec ted by the rule make it imperative that judges—and in s o me cases j udges of [ t he Supreme] Court—make sure that it is correctly applied.”). This is illust rated by the fact that the outcome of a patent case, unlik e a defamation or ill egal search case, has littl e impact on how future cases
03-1269,-1286 3466 U.S. 485, 498 & 501 (1984) ; see also Anderson v. Bessemer City , 470 U.S. 564, 575 (1985) (“[R]eview of factual f i ndings un der the clearly-erroneous standard—with its deference to the trier of fact—is the rule, not the exception.”); Pullman-Standard v. United Steel Workers of Am. , 456 U.S. 273, 287 (1982) (“R ule 52(a) broadly requ ires that findings of fact not be set asi de unless clearly erroneous.”); United States v. United States Gypsum Co. , 333 U.S. 364, 394 ( 1948). Ev en th ose findings of fact based entirely on documentary evidenc e are entitled to deference. And e rson , 470 U.S. at 574 (“That [Rule 52(a)] goes on to emphasize the special deferenc e to be paid credibility determinations does not alter its clear command: Rule 52(a) ‘does not make exc e ptions or purport to exc l ude certain ca tegories of factual findings fr om the obligation of a court of appeals to accept a district court’s findings unless clearly erroneous.’” (quoting Pullman-Standard , 456 U.S. at 287)). In short, we are obligated by Rule 52( a) to revie w the factual findings of the district court that underlie the determination of claim construction for clear error. While this court may persist in the delus io n that claim construction is a purely legal determination, unaffected by underlying facts, it is pl ainly not the case. Claim construction is, or should be, made in cont ext: a claim should be interpreted both from the perspective of one of ordinar y skill in the art and in view of the state of the art at the time of inv ention. Se e Multiform Des i ccant s, Inc. v. Medzam, Ltd. , 133 F.3d 1473, 1477

are decided or on how future parties behave. Cf. id. at 501 n.17 (“Regard i ng c e rtain largely factual questions in some areas of t he law, the stakes—in terms of i m pact on future cases and future conduct

— are too great to entrust them finally to the judgment of the trier of fact.”). Even if claim construc tion did im plicate a c onstitutional value, it, unlik e the decisions underlying the First and Fourth Amendments, could readily be reduced, when distinguished from it s factual underpinnings, to “a neat set of legal rules

. ” Ornelas , 517 U.S. at 695-96 (quoting Ill. v. Gates , 462 U.S. 213, 232 (1983)).
03-1269,-1286 4(Fed. Cir. 1998) (“It is the pers on of ordinary skill in the field of the inv ention through whose eyes the claims are construed.”). T hese questions, which are cr itical to the correct interpretation of a claim, are inherently factual. They are hotly contested by the parties, not by resort to case law as one would expec t for legal issues, but based on testimony and documentary evidence. 5 During so calle d Markman “hearings,” which are often longer than jury tria ls, parties battle over experts offering conflicting evidence regarding who qu alifies as one of ordinary skill in the art; the meaning of pa tent terms to that person; the state of the art at the time of the invent ion; contradictory dictionary definitions and which woul d be c onsulted by t he skilled artisan; the scope of specialized terms; the problem a patent was solving; what is related or pertinent art; whether a construction was dis a llowed during prosecuti on; how one of skill in the art would understand statements dur ing prosecution; and on and on. In order to reconcile the parties’ inc onsistent s ubmissions and arrive at a sound interpretation, the dist rict court is required to sift through and we igh volumes of evidence. While this court treats the district court as an i n take clerk, whose only role is to collect, shuffle and collate evidenc e, the reality, as revealed by conventional practice, is far different. Even if the procedures employ ed by the dist rict court did not show that it is engaging in factfinding, the nature of t he questions underly ing claim construction illustrate that they are factual and should be reviewed in a ccordance with Rule 52(a). For each patent, for example, who qualifie s as one of ordinary skill in the a r t will differ,

5 That most of the cases now appealed to this court are “summary judgments” is irrelev ant. We have artifi cially renamed findings of fact as legal conclus i ons; the district courts have dutifully conformed to our fictional characterization, but this does not change the inherent nature of the inquiry. Of course, if the parties do not dispute the material facts, summary judgment is appropriate.

03-1269,-1286 5just as the state of the art at the time of inv ention will d i ffer. These subsidiary determinations are specific, mult ifarious and not susceptible to generalization; as such their resolution in one case will b ear very little, if at all, on the resolution of subsequent

cases. See Ornelas , 517 U.S. at 703 (“Law clarificat ion requir e s generalization, and some issues lend themselves to general iz ation much more than others.”); Pierce v. Underwood , 487 U.S. 552, 561- 62 (1988) (“Many questi ons that arise in litigation are not amenable to regulation by rule bec ause they inv o lve multifarious, fleeting, special, narrow facts that utterly resist general ization.” (quoting Maurice Rosenberg, Judic i al Discretion of the Trial Court, Viewed from Above , 22 Syracuse L. Rev. 635, 662 (1971))); Icicle Seafoods, In c. v. Worthington , 475 U.S. 709, 714 (1986) (rejecting de

novo review of factual questions, even w hen outcome determinative). That the determination of the m eaning of a particular t e rm in one patent will not necess a rily bear on the inter p retation of the same term in a su bsequent p a tent illustrates this point; while the term is the same, the under lying factual cont ext is different. It further proves that these ques tions (e.g., who qu alifies as one of ordinary skill in the art and what was th e state of the art at the time of invention, among ot hers) are implic itly being det e rmined in each case; because we refuse to acknowledge either their existence or importance, however, the manner of their resolution is never elucidated. Finally, t hat claim construction is dependent on underlying factual determinations has been v e rified by our experience, which shows that r e viewing these questions de novo has not clarified the law, but has instead “distor t[ed] the appellate process, ” causing c onfusion among the district courts and bar. See C ooter , 496 U. S. at 404 (quoting Pie r ce , 487 U.S. at 561); see also Koon v. United States , 518 U.S. 81, 99 (1996).

03-1269,-1286 6Our purely de novo review of c l aim interpretati on als o cannot be reconciled wit h the Supreme Court’s instructions regarding obviousness. While ultimately a question of law, obviousness depends on several underlying factual inquiries. Graham v. Joh n Deere Co. , 383 U.S. 1, 17 (1966); see als o Dennison Mfg. Co. v. Panduit Corp. , 475 U.S. 809, 811 (1986) ( holding that Rule 52(a) requires that the dist rict court’s subsidiar y factual determinations should be reviewed for clear error); cf. Graver Tank & Mfg. Co. v. Linde Air Prods. Co. , 336 U.S. 271, 275 (1949) (holding that validity, while ultimately a question of law, is founded on f a ct ual determinations that are entitled to deference). “Under [section] 103, the scope and content of the prior art are to be determined; differences between t he prior art and the c l aims at iss ue are to be ascertained; and the level of ordinary skill in t he pertinent art resolved.” Graham , 383 U.S. at 17. To a significant degree, each of these factual inquiries is als o nec e ssary to claim construction. Before beginning claim constr uction, “the scope and content of the prior art [should] be determi ned,” id. , to establish context. The “d ifferences betwee n the prior art and the claims at issue [should] be ascertained,” id. , to better define what the inventor holds out as the in vention. And, the foundatio n for both the obvious ness and claim construction determination s is “the leve l of ordinary skill in the pertinent art.” Id. ;

see Multiform , 133 F.3d at 1477. These underlyin g fa ctual considerations receive the level of def erence due under Ru le 52(a) when considering obv iousness, but they are scrutinized de novo in the claim construction context. As directed by the Supreme Court, however, it is especially important in the patent fi eld, “where so much depend s upon familiarity with s pecific sc ientific problems and principles not usually contained in the general storehouse of knowl edge and experience,” to give def erence to the district

03-1269,-1286 7court’s findings of fact. Graver Tank & Mfg. Co. v. Linde Air Prods. Co. , 339 U.S. 605, 609-10 (1950). While the court flails about in an atte mpt to solv e the claim construction “conundrum,” the solution to our plight is straightforward. We simply must follow the example of every other appellat e court, which, regar ding the v a st majority of factual questions, reviews the tria l court for clear error. 6 This equilibrium did not come about as the result of chance or permi ssive appellate personal ities, but because two ce nturies of experience has shown that the trial court’ s factfinding ability is “unchallenged.” Salv e Regina Coll. v. Ru ssell , 499 U.S. 225, 233 (1991); Inwood , 456 U.S. at 856 (“Determining the weight and credi b ility of the eviden ce is t he specia l province of the trier of fact.”). Time has si milar l y revealed that it is mo re economical for the district court to find facts. Pierce , 487 U.S. at 560 (“Moreover, ev en where the district judge’s full knowledge of the factual setting can be acquir ed by the appellate court, that acquis i tion will often come at unusual expense, requiring the c ourt to undertake the unaccustomed task of reviewing the entire record . . . .”). Therefore, not only is it mo re efficient for th e trial court to constr uct the rec o rd, the trial court is better , that is, more accur a te, by way of both position and practice, at finding facts than appellate judges. And e rson , 470 U.S. at 574 (“The rationale fo r deference to the original finder of fact is not limited to the superiority of t he trial judge’s position to make determinations of credibili ty. The trial judge’s major role is the determination of fact, and with exp e rience on fu lfillin g that role comes expertise.”); Zenith Radio Corp. v. Hazeltine Research, Inc. , 395 U.S. 100, 123 (1969). Our rejecti o n

6 While jurisprudentially sound, the bar also supports this proposition, as evident by the many amici curiae briefs urging adherenc e to Rule 52(a).
03-1269,-1286 8of this fundamental pr emise has resulted, not surprisingly, in several serious problems, including increased litigation costs, needless consumption of judicial resources, and uncertainty, as well as diminished respect for the court and less “decisional accuracy.” Salve , 499 U.S. at 233. We s hould abandon this unsound course. 7 If we persist in dec iding the subsidiary fact ual c o mponents of claim construction without def erence, there is no r eason why lit igants should be r equired to parade their evidenc e before the district courts or for di strict courts to waste time and resources evaluating such evidence. It is excess iv e to require parties, who “have already been forced to concentrate their energies and r e sources on persuading t he trial judge that their account of the facts is the correct one,” to “persuade three more judges at the appellate level.” And e rson , 470 U.S. at 575. If the proceedi ngs before the district court are merely a “tryout on the road,” id. (quoting Wainwright v. Sykes , 433 U.S. 72, 90 (1977)), as they are under our current regi men, it is wasteful to require such proceedings at all. Instead, all patent case s could be filed in th is court; we would determine whether claim construction is ne cessary, and, if so, the meaning of the claims. Those few cases in which c l aim construction is not dispositive can be remanded to the district court for trial. In th is way, we would at le ast eliminate the time and expense of the charade currently play ed out before the district court. Eloquent words can mask much mischief. The cour t’s opinion today is ak in to rearranging the deck chairs on the Titanic

— the orchestra is playing as if nothing is amiss, but the ship is still head ing for Davey Jones’ lock e r

.

7 There are some scenarios where it is difficult to weed facts from law, see Pullman-Standard , 456 U.S. at 288, but claim c onstruction is not one of them.
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