717 Madison Place

Westinghouse Electric & Mfg. Co. v. Formica Insulation Co., 266 U.S. 342, 45 S.Ct. 117, 69 L.Ed. 316 (1924)

As between the owner of a patent and the public, the scope of the right of exclusion granted is to be determined in the light of the state of the art at the time of the invention. Can the state of the art be shown in a suit by the assignee of a patent against the assignor for infringement to narrow or qualify the construction of the claims and relieve the assignor from the charge? The Circuit Court of Appeals for the Seventh Circuit in Siemens-Halske Electric Co. v. Duncan Electric Co., 142 Fed. 157, seems to exclude any consideration of evidence of this kind for such a purpose. The same view is indicated in subsequent decisions of that court. Chicago & Alton Ry. Co. v. Pressed Steel Car Co., 243 Fed. 883, 887; Foltz Smokeless Furnace Co. v. Eureka Smokeless Furnace Co., 256 Fed. 847. We think, however, that the better rule, in view of the peculiar character of patent property, is that the state of the art may be considered. Otherwise the most satisfactory means of measuring the extent of the grant the Government intended and which the assignor assigned would be denied to the court in 351*351 reaching a just conclusion. Of course, the state of the art can not be used to destroy the patent and defeat the grant, because the assignor is estopped to do this. But the state of the art may be used to construe and narrow the claims of the patent, conceding their validity. The distinction may be a nice one but seems to be workable. Such evidence might not be permissible in a case in which the assignor made specific representations as to the scope of the claims and their construction, inconsistent with the state of the art, on the faith of which the assignee purchased; but that would be a special instance of estoppel by conduct. We are dealing only with the estoppel of an assignment based on the specifications and claims without special matter in pais.

Moto-Mower Co. v. E. C. Stearns & Co. Inc., 126 F.2d 854 (2d Cir. 1942).

The interpretation of the breadth of these claims must rest on the prior art. 856*856 Three prior patents — Davis 750,616, Olds 1,131,156, both cited to the Patent Office when Jenkins’ patent was before it, and Dale 961,485 — are relied on by defendant. It is sufficient to state that these three patents all disclose a lawn mower operated by a motor with a clutch for disengaging the motor. In Davis, the clutch is between the motor and the ground wheel, which latter drives the cutter; in Olds, between the cutter and ground wheel; and in Dale, there are two clutches disengaging both ground wheels from motor and cutter from motor. From these disclosures it follows that the claims in Jenkins’ patent must be read narrowly; that is, Jenkins must rest on the specific manner in which he disengages the various parts from operation.

Remington Rand, Inc. v. Meilink Steel Safe Co., 140 F.2d 519 (6th Cir. 1944)

In a case where the only issue is one of infringement, evidence of prior patents and prior use may be considered for the purpose of construing the patent, and although all of the elements of a patented combination are not found in a single structure in the prior art so as to fully anticipate, in determining the scope of the patent and its place in the art as affecting the question of infringement, prior patents showing separate elements of the combination, may properly be considered. Ventilated Cushion & Spring Co. v. D’Arcy, 6 Cir., 232 F. 468.

The patent in question must be considered in the light of the state of the art at the time it was granted (Cincinnati Cadillac Company v. English & Mersick Co., 6 Cir., 18 F.2d 542) and its claims must be construed in the light of its specifications and drawings. Knapp v. Morss, 150 U.S. 221, 228, 14 S.Ct. 81, 37 L.Ed. 1059.

Graham v. John Deere Co., 383 U.S. 1, 33, 86 S.Ct. 684, 15 L.Ed.2d 545 (1966)

It is, of course, well settled that an invention is construed not only in the light of the claims, but also with reference to the file wrapper or prosecution history in the Patent Office. Hogg v. Emerson, 11 How. 587 (1850); Crawford v. Heysinger, 123 U. S. 589 (1887). Claims as allowed must be read and interpreted with reference to rejected ones and to the state of the prior art; and claims that have been narrowed in order to obtain the issuance of a patent by distinguishing the prior art cannot be sustained to cover that which was previously by limitation eliminated from the patent. Powers-Kennedy Co. v. Concrete Co., 282 U. S. 175, 185-186 (1930); Schriber Co. v. Cleveland Trust Co., 311 U. S. 211, 220-221 (1940).

Autogiro Co. of America v. United States, 181 Ct.Cl. 55, 384 F.2d 391, 399, 155 USPQ 697, 704 (1967)

File wrapper. — The file wrapper contains the entire record of the proceedings in the Patent Office from the first application papers to the issued patent. Since all express representations of the patent applicant made to induce a patent grant are in the file wrapper, this material provides an accurate charting of the patent’s pre-issuance history. One use of the file wrapper is file wrapper estoppel, which is the application of familiar estoppel principles to Patent Office prosecution and patent infringement litigation. The patent applicant must 399*399 convince the patent examiner that his invention meets the statutory requirements;^[10] otherwise, a patent will not be issued. When the application is rejected, the applicant will insert limitations and restrictions for the purpose of inducing the Patent Office to grant his patent. When the patent is issued, the patentee cannot disclaim these alterations and seek an interpretation that would ignore them. He cannot construe the claims narrowly before the Patent Office and later broadly before the courts.^[11] File wrapper estoppel serves two functions in claim interpretation; the applicant’s statements not only define terms, but also set the barriers within which the claim’s meaning must be kept. These results arise when the file wrapper discloses either what the claim covers or what it does not cover.

The file wrapper also has a broader and more general use. This is its utilization, like the specification and drawings, to determine the scope of claims.^[12] For example, the prior art cited in the file wrapper is used in this manner. In file wrapper estoppel, it is not the prior art that provides the guidelines, but the applicant’s acquiescence with regard to the prior art. In its broader use as source material, the prior art cited in the file wrapper gives clues as to what the claims do not cover. Westinghouse Electric & Mfg. Co. v. Formica Insulation Co., 266 U.S. 342, 45 S.Ct. 117, 69 L.Ed. 316 (1924); Remington Rand, Inc. v. Meilink Steel Safe Co., 140 F.2d 519 (6th Cir. 1944). Moto-Mower Co. v. E. C. Stearns & Co. Inc., 126 F.2d 854 (2d Cir. 1942).

Fromson v. Advance Offset Plate, Inc., 720 F.2d 1565, 1566-67 (Fed.Cir.1983)

and

Fromson v. Advance Offset Plate, Inc., 720 F.2d 1565, 1569-71, 219 USPQ 1137, 1140-42 (Fed.Cir.1983)

At the time of the Fromson invention, the state of the art was depicted generally by U.S. Patent 2,714,006, issued on July 26, 1955 to Jewett and Case (Jewett). Jewett teaches the preparation of a presensitized lithographic plate by: first treating the surface of an aluminum sheet with an aqueous solution of an alkali metal silicate to form a water insoluble, hydrophilic, siliceous, organophobic surface layer; treating that layer with a diazo compound to form a light-sensitive, water soluble, diazo coating; and exposing portions of the coated plate to light through a negative or stencil, thus causing the exposed portions to become water insoluble, hydrophobic, organophilic image areas. The plate is then washed 1567*1567 with water to remove the water soluble diazo portions that were not exposed to light, thereby exposing the water insoluble, hydrophilic, organophobic, siliceous surfaces in their place (non-image areas). An image developer or printer’s developing ink is poured on the plate and the excess wiped off, making the image areas plainly visible. The plate is then ready for mounting on a press, successive treatments with water and ink, and printing. In this process, the image areas absorb ink while the non-image areas repel it.

…

The foregoing is fully consistent with long-standing use of “reaction” in the lithography art. Claims are normally construed as they would be by those of ordinary skill in the art. See e.g., Schenck v. Nortron Corp., 713 F.2d 782, 785, 218 USPQ 698, 701-02 (Fed.Cir.1983). Jewett interchangeably uses terms such as “treating”, “treatment”, and “react”, to describe a lithographic plate producing process. Jewett’s claims use “reacting”, “treatment”, and “reaction product”. Jewett makes no attempt to define the structure of the layer there disclosed (as an aluminosilicate compound or otherwise), although it does mention the hydrophilic layer as being chemically bonded to the aluminum surface. Jewett refers to the layer as “silicate treatment”, as “silicate or silicon containing” film, or as “an inorganic material such as silicate”. It is not unreasonable to conclude that one of ordinary skill in the lithography art would interpret “react” in Fromson to mean the same thing it appears to mean in Jewett, i.e., the treatment of a metal substrate with an aqueous solution to yield a layer, regardless of the chemical structure of the layer or the proper label for the phenomena that produced it.

[Jewett patent was mentioned in the specification of Fromson’s patent]

Tandon Corp. v. International Trade Comm’n, 831 F.2d 1017, 1021, 4 USPQ2d 1283, 1286 (Fed.Cir.1987)

Claim interpretation is a question of law, having factual underpinnings. When the meaning of key terms of claims is disputed, as in this case, extrinsic evidence may be adduced including testimony of witnesses, and reference may be had to the specification, the prosecution history, prior art, and other claims. H.H. Robertson, Co. v. United Steel Deck, Inc., 820 F.2d 384, 389, 2 USPQ2d 1926, 1929 (Fed.Cir.1987); SRI International v. Matsushita Electric Corp. of America, 775 F.2d 1107, 1117 n. 11, 1118, 227 USPQ 577, 582 n. 11, 583 (Fed.Cir.1985). Claims may not be construed one way in order to obtain their allowance and in a contrary way against infringers. Autogiro Company of America v. United States, 384 F.2d 391, 398-99, 181 Ct.Cl. 55, 155 USPQ 697, 703-04 (1967). When the interpretation of claims requires findings of underlying fact, those factual findings are reviewed in accordance with the appropriate evidentiary standard, i.e., that of substantial evidence. Texas Instruments, Inc. v. U.S. International Trade Commission, 805 F.2d 1558, 1562 n. 2, 231 USPQ 833, 834 n. 2 (Fed.Cir.1986).

SRI International v. Matsushita Electric Corp. of America, 775 F.2d 1107, 1117 n. 11, 1118, 227 USPQ 577, 582 n. 11, 583 (Fed.Cir.1985)

To understand what is being claimed in each claim one must often refer to the specification, prosecution, and prior art. One must do so to resolve any ambiguity in claim language. Use may be made by either party of materials extraneous to the words of a claim, to give them a “special meaning” which will support an assertion of actual infringement/non-infringement under the doctrines of equivalents/reverse equivalents. That use does not change the answer to the question of whether the claim language as written “reads on” the accused device, which is synonymous with what has long been called “literal infringement”. As the text makes clear, determination that the claim words read literally on the accused device is but an “initial hurdle”. See Autogiro Co. of America v. United States, 384 F.2d 391, 399, 181 Ct.Cl. 55, 155 USPQ 697, 704 (1967).

Lemelson v. General Mills, Inc., 968 F. 2d 1202, 1206 (Fed. Cir. 1992)

In determining the meaning of a claim, it is necessary to examine closely the language of the claim, the specification, and the prosecution history. See, e.g., Fromson v. Advance Offset Plate, Inc., 720 F.2d 1565, 1569-71, 219 USPQ 1137, 1140-42 (Fed.Cir.1983). This is particularly true if, as is often the case, a dispute exists as to how language of the claim should be interpreted and the claim as a whole construed. The prosecution history gives insight into what the applicant originally claimed as the invention, and often what the applicant gave up in order to meet the Examiner’s objections. Prosecution history is especially important when the invention involves a crowded art field, or when there is particular prior art that the applicant is trying to distinguish.

Markman, 52 F.3d at 979-80

Further, it is only fair (and statutorily required) that competitors be able to ascertain to a reasonable degree the scope of the patentee’s right to exclude. Merrill v. Yeomans, 94 U.S. at 573-74 (“It seems to us that nothing can be more just and fair, both to the patentee and to the public, than that the former should understand, and correctly describe, just what he has invented, and for what he claims a patent.”); Hogg v. Emerson, 47 U.S. (6 How.) at 484. They may understand what is the scope of the patent 979*979 owner’s rights by obtaining the patent and prosecution history — “the undisputed public record,” Senmed, 888 F.2d at 819 n. 8, 12 USPQ2d at 1512 n. 8 — and applying established rules of construction to the language of the patent claim in the context of the patent. Moreover, competitors should be able to rest assured, if infringement litigation occurs, that a judge, trained in the law, will similarly analyze the text of the patent and its associated public record and apply the established rules of construction, and in that way arrive at the true and consistent scope of the patent owner’s rights to be given legal effect.

Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996)

Third, the court may also consider the prosecution history of the patent, if in evidence. Id. at 980, 52 F.3d 967, 34 USPQ2d at 1330; Graham v. John Deere, 383 U.S. 1, 33, 86 S.Ct. 684, 701-02, 15 L.Ed.2d 545, 148 U.S.P.Q. 459, 473 (1966). This history contains the complete record of all the proceedings before the Patent and Trademark Office, including any express representations made by the applicant regarding the scope of the claims. As such, the record before the Patent and Trademark Office is often of critical significance in determining the meaning of the claims. See Markman, 52 F.3d at 980, 34 USPQ2d at 1330; Southwall 1583*1583 Tech., Inc. v. Cardinal IG Co., 54 F.3d 1570, 1576, 34 USPQ2d 1673, 1676 (Fed.Cir. 1995) (“The prosecution history limits the interpretation of claim terms so as to exclude any interpretation that was disclaimed during prosecution.”) (citations omitted). Included within an analysis of the file history may be an examination of the prior art cited therein. Autogiro Co. of America v. United States, 181 Ct.Cl. 55, 384 F.2d 391, 399, 155 USPQ 697, 704 (1967) (“In its broader use as source material, the prior art cited in the file wrapper gives clues as to what the claims do not cover.”).

Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1584-85 (Fed. Cir. 1996)

In addition, a court in its discretion may admit and rely on prior art proffered by one of the parties, whether or not cited in the specification or the file history. This prior art can often help to demonstrate how a disputed term is used by those skilled in the art. Such art may make it unnecessary to rely on expert testimony and may save much trial time. As compared to expert testimony, which often only indicates what a particular expert believes a term means, prior art references may also be more indicative of what all those skilled in the art generally believe a certain term means. Once again, however, reliance on such evidence is unnecessary, and indeed improper, when the disputed terms can be understood from a careful reading of the public record. See Kearns v. Chrysler Corp., 32 F.3d 1541, 1547, 31 USPQ2d 1746, 1750 (Fed.Cir.1994). Nor may it be used to vary claim terms from how 1585*1585 they are defined, even implicitly, in the specification or file history.

Arthur A. Collins, Inc. v. Northern Telecom Ltd., 216 F.3d 1042 (Fed.Cir.2000),

The district court construed the TST switch limitation to require a three-stage switch. The first and third stages are time switches, which allow a change in the time slot occupied by a channel of data within a frame of channels. The first and third stages include the ports of the TST switch, with each port having a memory. The second stage is a single-stage space switch, which performs a change in the physical transmission path of a channel. To reach that construction of the TST switch limitation, the court relied primarily on the sole embodiment of the invention set forth in the written description and illustrated in figure 3 of each patent. Although the written description refers to TST switches and systems disclosed and claimed in several other patents, the court declined to consider the teachings of those patents to ascertain the meaning of the term as used in the ‘589 and ‘907 patents or as understood by a person skilled in the telecommunications art.

In construing the TST switch limitation, the district court properly consulted the written description and figure 3 of the patent. See, e.g., CVI/Beta Ventures, Inc. v. Tura LP, 112 F.3d 1146, 1153, 42 USPQ2d 1577, 1583 (Fed.Cir.1997). The written description and the drawing, however, do not suggest that Collins was using the term “TST switch” in a special manner in the two patents. In particular, nothing in the claims, descriptions, or drawings of the ‘589 and ‘907 patents requires limiting the TST switch to a single-stage space switch. Nor does any point of novelty or asserted advantage of the Collins inventions depend on the TST switch having a single-stage space switch. Accordingly, the normal rule of construing patent terms as persons skilled in the art would understand them applies in this case.

Even when prior art is not cited in the written description or the prosecution history, it may assist in ascertaining the 1045*1045 meaning of a term to a person skilled in the art. See Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1584, 39 USPQ2d 1573, 1578 (Fed.Cir.1996). When prior art that sheds light on the meaning of a term is cited by the patentee, it can have particular value as a guide to the proper construction of the term, because it may indicate not only the meaning of the term to persons skilled in the art, but also that the patentee intended to adopt that meaning.

The ‘589 and ‘907 patents note that “system improvements attainable with time division transmission and switching techniques are very significant, and have resulted in the development of TST switches and systems described and claimed in, for example, U.S. Pat. Nos. 3,925,621; 3,956,593; 4,005,272; and 4,038,497.” ‘589 patent, col. 2, ll. 9-14; ‘907 patent, col. 2, ll. 1-6. The cited patents indicate that switches with time-switch inputs and outputs and with multiple intermediate space switches are referred to as TST switches, even though such structures can also be called, for example, TSSST switches. Based on the way the term “TST switch” is used in those patents, and the absence of any indication in Collins’s patents or in their prosecution histories that the term was meant to have a different meaning in the ‘589 and ‘907 patents, we agree with Collins that the TST switch limitation allows a multiple-stage space switch, rather than just a single-stage space switch.

Tate Access Floors, Inc. v. Interface Architectural Res., Inc., 279 F.3d 1357, 1371-72 n.4 (Fed. Cir. 2002)

Contrary to Interface’s next contention, nothing in the prosecution history, or elsewhere in the prior art of record,^[4] renders proper a construction that limits the claimed “border” to a single, horizontal layer. Interface would have us adopt its narrow construction in order to preserve the validity of the ‘491 patent. It contends that the prior art would render the asserted claims obvious if they cover floor panels with simple beveled edges such as its accused products.

[4] In construing claims, we look first to the intrinsic evidence of record — the patent, including the claims, remainder of the specification, and, if it is in evidence, the prosecution history. Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582, 39 USPQ2d 1573, 1576 (Fed.Cir.1996). The court may not vary the meaning of claim language when that meaning is clear from the intrinsic evidence. Prior art cited in the prosecution history falls within the category of intrinsic evidence. Prior art the examiner failed to consider is extrinsic. In the present case, however, we will discuss all of the prior art on which Interface now seeks to rely, because none of it compels its narrow construction of the term “border.”

Kumar v. Ovonic Battery Co., 351 F.3d 1364, 1368 (Fed. Cir. 2003)

Our cases also establish that prior art cited in a patent or cited in the prosecution history of the patent constitutes intrinsic evidence. Tate Access Floors, Inc. v. Interface Architectural Res., Inc., 279 F.3d 1357, 1371-72 n. 4 (Fed.Cir.2002); Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed.Cir.1996); Markman, 52 F.3d at 979-80. For example, in Arthur A. Collins, Inc. v. Northern Telecom Ltd., 216 F.3d 1042 (Fed.Cir.2000), we rejected the district court’s claim construction, which “declined to consider the teachings of [prior art referenced in the patent] to ascertain the meaning” of the claim term “time-space-time (TST) switch.” Id. at 1044. Instead, we interpreted the term based on its usage in the prior art that was cited in the patent, explaining that “[w]hen prior art that sheds light on the meaning of a term is cited by the patentee, it can have particular value as a guide to the proper construction of the term, because it may indicate not only the meaning of the term to persons skilled in the art, but also that the patentee intended to adopt that meaning.” Id. at 1045.

In the present case, the Polk patent is not simply cited in the ‘686 patent as pertinent prior art; nor is there any showing that the Polk patent adopted a special definition at variance with that prevailing in the art. Rather the Polk patent was considered by both the applicant and the examiner to be highly pertinent prior art, and there is no indication that the Polk patent’s express definition (even if inconsistent with the general dictionary definition) was in any way at variance with the definition that would have been used by those skilled in the art at the time. Indeed, as noted below, Ovonic’s own ‘440 patent, though issued some few years after the issuance of the Kumar patent, uses the same definition, thus at least suggesting that the “long range order” definition was not unique to the Polk patent.

Under these circumstances, we conclude that the Polk patent definition is to be preferred over the general dictionary definition relied upon by Ovonic. This Polk patent definition should control unless the specification clearly states an alternative meaning or this meaning was disclaimed during prosecution. See Inverness I, 309 F.3d at 1371-72. Here, the specification and prosecution history do not require a different interpretation than the Polk patent’s definition of an amorphous alloy, namely one “in which the constituent atoms are arranged in a spatial pattern that exhibits no long range order….” Polk patent, col. 1, ll. 13-15.

V-Formation, Inc. v. Benetton Group SpA, 401 F. 3d 1307 (Fed. Cir. 2005)

The district court properly considered other intrinsic evidence to aid its construction. For instance, the district court considered U.S. Patent No. 5,549,310 (issued August 27, 1996) (the Meibock patent). The Meibock patent is prior art that was listed as a reference on the face of the ‘466 patent and in an Information Disclosure Statement. This prior art reference to Meibock is not extrinsic evidence. This court has established that “prior art cited in a patent or cited in the prosecution history of the patent constitutes intrinsic evidence.” Kumar v. Ovonic Battery Co., 351 F.3d 1364, 1368 (Fed.Cir.2003); Tate Access Floors, Inc. v. Interface Architectural Res., Inc., 279 F.3d 1357, 1371-72 n. 4 (Fed.Cir.2002); Vitronics, 90 F.3d at 1582 (Fed.Cir.1996); Markman, 52 F.3d at 979-80. For example, in Arthur A. Collins, Inc. v. Northern Telecom Ltd., 216 F.3d 1042 (Fed.Cir.2000), this court rejected the district court’s claim construction, which “declined to consider the teachings of [prior art referenced in the patent] to ascertain the meaning” of the claim term “time-space-time (TST) switch.” Id. at 1044. Instead, this court interpreted the term based on its usage in the prior art that was cited in the patent, explaining that “when prior art that sheds light on the meaning of a term is cited by the patentee, it can have particular value as a guide to the proper construction of the term, because it may indicate not only the meaning of the term to persons skilled in the art, but also that the patentee intended to adopt that meaning.” Id. at 1045.

Phillips v. AWH Corp., 415 F. 3d 1303, 1317 (Fed. Cir. 2005)

In addition to consulting the specification, we have held that a court “should also consider the patent’s prosecution history, if it is in evidence.” Markman, 52 F.3d at 980; see also Graham v. John Deere Co., 383 U.S. 1, 33, 86 S.Ct. 684, 15 L.Ed.2d 545 (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 Patent Office.”). The prosecution history, which we have designated as part of the “intrinsic evidence,” consists of the complete record of the proceedings before the PTO and includes the prior art cited during the examination of the patent. Autogiro, 384 F.2d at 399. Like the specification, 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 prosecution history was created by the patentee in attempting to explain and obtain the patent. Yet because the prosecution history represents an ongoing negotiation between the PTO and the applicant, rather than the final product of that negotiation, it often lacks the clarity of the specification and thus is less useful for claim construction purposes. See Inverness Med. Switz. GmbH v. Warner Lambert Co., 309 F.3d 1373, 1380-82 (Fed.Cir.2002) (the ambiguity of the prosecution 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” for 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 course of prosecution, making the claim scope narrower than 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).

LG Electronics, Inc. v. Bizcom Electronics, Inc., 453 F. 3d 1364 (Fed. Cir. 2006)

But, this does not end our inquiry. The proper claim construction is “the ordinary and customary 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.” Phillips, 415 F.3d at 1313 (citations omitted). “When prior art that sheds light on the meaning of a term is cited by the patentee, it can have particular value as a guide to the proper construction of the term, because it may indicate not only the meaning of the term to persons skilled in the art, but also that the patentee intended to adopt that meaning.” Arthur A. Collins, Inc. v. N. Telecom Ltd., 216 F.3d 1042, 1045 (Fed. Cir.2000). Although we have concluded that the patentee did not expressly adopt the definition of “requesting agent” in the incorporated industry standard, that standard remains relevant in determining the meaning of the claim term to one of ordinary skill in the art at the time the patent application was filed, and it is treated as intrinsic evidence for claim construction purposes, see V-Formation, Inc. v. Benetton Group SpA, 401 F.3d 1307, 1311 (Fed. Cir.2005) (“This court has established that `prior art cited in a patent or cited in the prosecution history of the patent constitutes intrinsic evidence.'”) (citations omitted).