OVERVIEW of an INFRINGEMENT ANALYSIS for U.S. UTILITY PATENT by John C. Garvey the Following Is a Summary of the Basic Issues Wh

OVERVIEW OF AN INFRINGEMENT ANALYSIS FOR U.S. UTILITY PATENT

By John C. Garvey

The following is a summary of the basic issues which the U. S. Supreme Court and the Court of Appeals for the Federal Circuit (“Federal Circuit”) indicate should be considered by anyone performing an infringement analysis. The issues are discussed in the order presented on the attached Infringement Analysis Diagram. This is not meant to indicate that the issues must be considered in this order, or that all issues are pertinent to every infringement analysis. For example, decisions written by the courts tend to focus on only those issues which are relevant to the facts of the case being decided. However, anyone performing an infringement analysis should at least consider whether each of these issues is pertinent to the facts of the situation being analyzed.

CLAIM CONSTRUCTION

The first step in any infringement analysis is to interpret or construe the claim language. The focus in construing a claim term is on what one of ordinary skill in the art at the time of the invention, would have understood the term to mean. Markman v. Westview Instruments, Inc., 52 F.3d 967, 34 USPQ2d 1321, 1335 (Fed. Cir. 1995) (en banc), affirmed 116 SCt 1384, 38 USPQ 2d 1461 (1996). Three sources are used to construe the meaning of claims: the claims, the specification, and the prosecution history. Markman, 34 USPQ2d at 1329. While extrinsic evidence such as expert testimony may be used to assist a court in construing the claims, such extrinsic evidence cannot be used to vary or contradict the terms of the claims as explained in the patent or prosecution history. See Markman, 34 USPQ2d at 1331. In particular, expert testimony on the meaning of a claim term to one of ordinary skill at the time of the invention cannot be relied on to construe a claim term when it appears from the patent and the prosecution history that the claim term was used differently by the applicant. Southw all Technology, Inc. v. Cardinal IG Co., 54 F.3d 1570, 34 USPQ2d 1673, 1678 (Fed. Cir. 1995). Also, the claims should not be interpreted in light of the potentially infringing device. SRI Int'l v. Matsushita Electric Corp. of America, 775 F.2d 1107, 227 USPQ 577 (Fed. Cir. 1985).

The Federal Circuit has previously taken the position that “[d]ictionaries, encyclopedias and treatises, publicly available at the time the patent is issued, are objective resources that serve as reliable sources of information on the established meanings that would have been attributed to the terms of the claims by those of skill in the art.” Texas Digital Systems, Inc. v. Telegenix, Inc., 64 U.S.P.Q.2d 1812, 1818 (Fed. Cir. 2002). Once the meaning of a claim term is ascertained based, for example, on a dictionary, the intrinsic record (i.e., the specification, claims and prosecution history) “must always be consulted to identify which of the different possible dictionary meanings of the claim terms in issue is most consistent with the use of the words by the inventor.” Id. at 1819. That is, the intrinsic record may show that only one of a number of different definitions is applicable to a claim term. Alternatively, it is possible that the intrinsic record will be inconsistent with one or all of the dictionary definitions. Thus, “the presumption in favor of a dictionary definition will be overcome where the patentee, acting as his or her own lexicographer, has clearly set forth an explicit definition of the term different from its ordinary meaning.” Id. The presumption is also rebutted ”if the inventor has disavowed or disclaimed scope of coverage, by using words or expressions of manifest exclusion or restriction, representing a clear disavowal of claim scope.” Id.

In Phillips v. AWH Corp., the Federal Circuit clarified the use of extrinsic and intrinsic evidence in claim construction. 415 F.3d 1303, 75 USPQ2d 1321 (Fed. Cir. 2005) (en banc). Prior to Phillips, some court cases suggested a greater emphasis on dictionary definitions of claim terms and gave less significance to the specification and prosecution history. If more than one of the dictionary definitions was consistent with the intrinsic record, the claim terms could encompass all the consistent meanings. Phillips, 415 F.3d at 1319, 75 USPQ2d at 1332. In Phillips, the court recognized the “systematic over-breadth” of this approach, and stated that the court should instead focus “at the outset on how the patentee used the claim term in the claims, specification, and prosecution history, rather than starting with a broad definition and whittling it down.” Phillips, 415 F.3d at 1321, 75 USPQ2d at 1333. Thus, intrinsic evidence is the key to claim interpretation.

EXAMPLE: If a claim recites "a golf ball having a cover with large dimples," there might be some dispute as to the true meaning of the term "large." The specification and prosecution history would be considered in order to determine the meaning of the term "large." The remaining terms would be given their ordinary meaning.

An important step in claim interpretation is identifying whether the claim has any "means- plus- function" limitations. A "means-plus-function" limitation is defined as "an element in a claim for a combination ... expressed as a means or step for performing a specified function without the recital of structure, material or acts in support thereof ..." 35 U.S.C.§112, ¶6. W hen the claim under consideration includes "means-plus- function" language, 35 U.S.C. §112, ¶6 requires that this language "be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof." Therefore, properly interpreted means-plus-function language is limited because it covers only the structure, material, or acts described in the specification and their equivalents. Valmont Industries, Inc. v. Reinke Manufacturing Co., Inc., 983 F.2d 1039, 25 USPQ2d 1451 (Fed. Cir. 1993).

"In determining whether to apply the statutory procedures of section 112, ¶6, the use of the word 'means' triggers a presumption that the inventor used this term advisedly to invoke the statutory mandates for means-plus-function clauses." York Products, Inc. v. Central Tractor Farm & Family Center, 99 F3d 1568, 40 USPQ2d 1619, 1623 (Fed. Cir. 1996). However, to "invoke this statute; the alleged means-plus-function claim element must not recite a definite structure which performs the described function." Cole v. Kimberly-Clark Corp., 102 F.3d 524, 41 USPQ2d 1001, 1006 (Fed. Cir. 1996).

Under the principle known as claim differentiation, limitations of a narrower claim (e.g., a dependent claim) must not be read into a broader claim (e.g., an independent claim). U.S. v. Telectronics, Inc., 857 F.2d 778, 8 USPQ2d 1217, 1221 (Fed. Cir. 1988) cert. denied, 109 S. T. 1954 (1989). However, the principle of claim differentiation is subservient to the mandate of 35 U.S.C. §112, ¶6. Therefore, a means-plus-function limitation cannot be made broader by inserting a dependent claim specifying the specific structure in non-means form. Laitram Corp. v. Rexnord, Inc., 939 F.2d 1533, 19 USPQ2d 1367 (Fed. Cir. 1991).

Other Federal Circuit decisions relating to the issue of claim construction or interpretation include: DMI, Inc. v. Deere & Co., 755 F.2d 1570, 225 USPQ 236 (Fed. Cir. 1985); McGill, Inc. v. John Zink Co., 736 F.2d 666, 221 USPQ 944 (Fed. Cir. 1984), cert. denied, 479 U.S. 931 (1986); and E.I. du Pont de Nemours & Co. v. Phillips Petroleum Co., 849 F.2d 1430, 7 USPQ2d 1129 (Fed. Cir. 1988), cert. denied, 488 U.S. 986 (1988); Catalina Marketing Int’l v. Coolsavings.Com, 289 F.3d 801 (Fed. Cir. 2002).

LITERAL INFRINGEMENT

Once the claim language has been properly construed, the next step is to determine whether or not literal infringement exists. Literal infringement may be found if a claim, as properly interpreted, reads on the alleged infringing device. Envirotech Corp. v. Al George, Inc., 730 F.2d 753, 221 USPQ 473 (Fed. Cir. 1984).

As indicated above, if a claim which reads on a potentially infringing device includes any limitations stated in terms of "means-plus-function" language, then it must be determined whether such a claim limitation is met literally. To make this determination one should "compare the accused structure with the disclosed structure, and must find equivalent structure as well as identity of claimed function for that structure." Pennw alt Corp. v. Durand-Wayland, Inc., 833 F.2d 931, 934, 4 USPQ2d 1737, 1739 (Fed. Cir. 1987) (en banc) cert. denied, 108 S. Ct. 1226 (1988). Therefore, in order for a claim including a means-plus-function limitation to be literally infringed, the accused device must employ structure which is identical to, or the equivalent of, the structure, material, or acts described in the patent specification. In addition, the accused device must also perform the identical function which is recited in the limitation. Valmont Industries, Inc. v. Reinke Manufacturing Co., Inc., supra. The Federal Circuit has also made it clear that means-plus-function limitations must always be interpreted in the same fashion regardless of whether the issue is infringement or validity before a court or patentability before the U.S. Patent and Trademark Office. In re Donaldson Co., Inc., 16 F.3d 1189, 29 USPQ2d 1845 (Fed. Cir. 1994).

W hat is an "equivalent" under 35 U.S.C. § 112, ¶6? The Federal Circuit has indicated that equivalency under 35 U.S.C. §112, ¶6 should not be confused with the doctrine of equivalents. In re Donaldson, supra. The Federal Circuit has defined an equivalent under §112, ¶6 as resulting "from an insubstantial change which adds nothing of significance to the structure, material, or acts disclosed in the patent specification." Valmont v. Reinke, supra, 983 F.2d at 1039, 25 USPQ2d at 1455. An important factor in the determination of §112, ¶6, equivalency is whether persons reasonably skilled in the art would have known of the interchangeability of an ingredient not contained in the patent (but which is part of the accused device) with one that was. Palumbo v. Don-Joy Co., 762 F.2d 969, 226 USPQ 5 (Fed. Cir. 1985). In determining equivalency under §112, ¶6, the courts have relied on expert testimony relating to the interchangeability of the accused structure and the disclosed "means." Therefore, when performing an infringement analysis, it is desirable to consult those of ordinary skill and any available reference materials in order to arrive at a determination regarding equivalency under 35 U.S.C. §112, ¶6.

Other Federal Circuit decisions relating to the issue of equivalency under 35 U.S.C. §112, ¶6 include: Chiuminatta Concrete Concepts, Inc., v. Cardinal Industries, Inc. 46 USPQ 2d 1752 (Fed Cir. 1998); Alpex Computer Corp. v. Nintendo Co., Ltd. 40 USPQ 2d 1667 (Fed. Cir. 1996); Johnston v. IVAC Corp., 885 F.2d 1574, 12 USPQ2d 1382 (Fed. Cir. 1989); and Durango Associates, Inc. v. Reflange, Inc., 843 F.2d 1349, 6 USPQ2d 1290 (Fed. Cir. 1988); Al-Site Corp. v. VSI Int’l, 174 F.3d 1308 (Fed. Cir. 1999).

Another rarely applicable consideration in a literal infringement analysis is the so-called "reverse doctrine of equivalents" under which no infringement is found even though a claim literally reads on an accused device. In particular, if an accused product or process is so far changed in principle that it performs the function of the claimed invention in a substantially different way, then there is no infringement despite the fact that the claim reads on the accused device. SRI Int'l v. Matsushita Electric Corp., 775 F.2d 1107, 227 USPQ 577, 578 (Fed. Cir.1985); and Westinghouse v. Boyden Pow er Brake Co., 170 U.S. 537, 568 (1898).

EXAMPLE: A claim recites "a ball comprising a liquid center and a dimpled cover surrounding the liquid center," in an application describing a new and improved golf ball. The accused device is a wrecking ball for use in construction, and the wrecking ball has a liquid center and a dimpled cover surrounding the liquid center. In this case, it is possible that a court would apply the reverse doctrine of equivalents to find no infringement.

INFRINGEMENT UNDER THE DOCTRINE OF EQUIVALENTS

Even if a claim is not literally infringed, infringement may be found under the Doctrine of Equivalents if "the differences between the claimed and accused products or processes are insubstantial". Hilton Davis Chemical Co. v. Warner-Jenkinson Co., 62 F.3d 1512, 35 USPQ2d 1641, 1644 (Fed. Cir. 1995). While holding that the application of the Doctrine of Equivalents rests on the "substantiality of the differences", the Federal Circuit in Hilton Davis indicated that the function-way-result test often suffices to assess equivalency. See Hilton Davis, 35 USPQ2d at 1645. The function-way-result test states that infringement may be found when an accused device and the claimed invention perform substantially the same function in substantially the same way to yield substantially the same result. Graver Tank & Mfg. Co. v. Linde Air Products Co., 339 U.S. 605, 608- 609, 85 USPQ 328, 330 (1950).

In Warner-Jenkinson Co. v. Hilton Davis Chemical Co. 520 U.S. 17, 117 S.Ct. 1040, 41 USPQ 2d 1865 (1997) the Supreme Court described the Doctrine of Equivalents as follows:

“Each element contained in a patent claim is deemed material to defining the scope of the patented invention, and thus, the doctrine of equivalents must be applied to individual elements of the claim, not to the invention as a whole.” (41 USPQ2d at 1871).

The Supreme Court did not articulate a specific test for infringement under the Doctrine of Equivalents but described the essential inquiry as follows:

"Does the accused product or process contain elements identical or equivalent to each claimed element of the patented invention?" (41 USPQ 2d at 1875).

The Court indicated that the triple identity test (function-way-result) may be useful for analyzing mechanical devices. The Court further indicated that when this test is used, the inquiry is whether “a substitute element matches the function, way, and result of the claimed element, or whether the substitute element plays a role substantially different from the claimed element.” (41 USPQ 2d at 1875). Subsequent to the Supreme Court's decision in Warner-Jenkinson, the Federal Circuit has expressly adopted the concept of applying the function- way-result test to claim elements:

“A patentee may prove this insubstantial change by showing that the substituted element in the accused device performs substantially the same function, in substantially the same way, to produce substantially the same result as the claimed element.”

Eastman Kodak Co. v Goodyear Tire & Rubber Co. 114 F. 3rd 1547, 42 USPQ 2d 1737, 1746 (Fed. Cir. 1997).

However, the Federal Circuit has indicated that it still applies the "insubstantial differences" test to determine infringement under the Doctrine of Equivalents despite the fact that the Supreme Court criticized this test in Warner-Jenkinson. Dawn Equipment Co. v. Kentucky Farms Inc., 46 USPQ2d 1109, 1113 (Fed. Cir. 1998). In Dawn Equipment, the Federal Circuit also took the position that the function-way-result test could be considered in appropriate cases for additional guidance on the question of equivalents Id at 46 USPQ2d at 1113.

In Hilton Davis, the Court made it clear that the application of the function-way-result test “does not necessarily end the inquiry.” See Hilton Davis, 35 USPQ2d at 1645. The Federal Circuit indicated that all evidence relevant to the substantiality of the differences should be considered, and specifically pointed out several factors which tend to indicate whether the differences between the claimed and accused products or processes are substantial or insubstantial. These factors include: 1) interchangeability of the different accused and claimed elements (tending to show differences to be insubstantial), 2) evidence of copying (tending to show differences to be insubstantial), and 3) evidence of designing around the patent claims (tending to show differences to be substantial). See Hilton Davis, 35 USPQ2d at 1646. In Roton Barrier, Inc. v. Stanley Works, 79 F.3d 1112, 37 USPQ2d, 1816, 1827 (Fed. Cir. 1996), the CAFC stated that "such designing around provides an inference of no infringement" under the doctrine of equivalents. In addition, the CAFC has suggested that the fact that the accused device is covered by a patent may be relevant to the issue of substantiality of the differences. National Presto Industries, Inc. v. West Bend Co., 76 F.3d 1185, 37 USPQ2d 1685, 1689 (Fed. Cir. 1996). The Supreme Court was not enthusiastic about the additional factors identified by the Federal Circuit, but instead took the position that "intent plays no role in the application of the Doctrine of Equivalents." (See Warner-Jenkinson 41 USPQ 2d at 1874). However, as indicated above, the Supreme Court has left the specific implementation of the test for infringement under the Doctrine of Equivalents to the Federal Circuit, indicating that it did not see any purpose in "micro- managing the Federal Circuit's particular word-choice for analyzing equivalence." (41 USPQ 2d at 1875-1876).

In applying the function-way-result test, it is often true that the elements of the accused device and the claimed invention will be found to perform the same function or work. If they do not, then probably no serious issue of infringement would have been raised in the first place. W ith respect to the substantially the same "result" part of the test, helpful evidence of the "result" produced by the claimed invention can often be obtained from the specification and prosecution history of the patent. For example, the patent specification might explain that the invention is particularly significant because a "compact" device is achieved. The specification might further explain that the device which is achieved has dimensions of 5 cm by 5 cm. In this case, if the accused device is much larger than 5 cm by 5 cm, then it could reasonably be determined that the accused device does not achieve "substantially the same result" as the claimed invention.

Finally, with respect to the "in substantially the same way" portion of the test, in Pennwalt, the Federal Circuit approved the lower court's application of an element-by-element analysis. In this analysis, also known as the "All Elements" rule, it is determined whether each claim element is the same as, or equivalent to, a corresponding structure in the accused device. In Corning Glass Works v. Sumitomo Electric, 868 F.2d 1251, 9 USPQ2d, 1962, 1968 (Fed. Cir. 1989), the Federal Circuit modified the "All Elements" rule, by stating that the equivalent must be found somewhere in the accused device, but not necessarily in the corresponding element. Therefore, it is more appropriate to refer to the "All Limitations" rule (instead of the "All Elements" rule) under which each limitation of a claim, or its substantial equivalent, must be found in the accused device for there to be infringement. Athletic Alternatives, Inc. v. Prince Manufacturing, Inc., 73 F.3d 1573, 37 USPQ2d 1365, 1373 (Fed. Cir. 1996).

The Federal Circuit has also made it clear that if equivalency exists, infringement will be found unless (1) prosecution history estoppel applies (in which case the patentee is estopped from asserting a range of equivalents broad enough to encompass the accused product or process based on claim amendments and/or patentability arguments made during prosecution) Loctite Corp. v. Ultraseal Ltd., 228 USPQ at 96; or (2) a hypothetical patent claim, sufficient in scope to literally cover the accused product, is not patentable over the prior art. Wilson Sporting Goods Co. v. David Geoffrey & Associates, 904 F.2d 677, 14 USPQ2d 1942, 1948 (Fed. Cir. 1990), cert. denied, 111 S. Ct. 537 (1990).

Other Federal Circuit decisions relating to the issue of the doctrine of equivalents include: London v. Carson Pirie Scott & Co., 946 F.2d 1534, 20 USPQ2d 1456 (Fed. Cir. 1991);

Slimfold Manufacturing Co., Inc. v. Kinkead Industries, Inc., 932 F.2d 1453, 18 USPQ2d 1842 (Fed. Cir. 1991); Sun Studs, Inc. v. ATA Equipment Leasing, Inc., 872 F.2d 978, 10 USPQ2d 1338 (Fed. Cir. 1989); Valmont Industries, Inc. v. Reinke Manufacturing Co., Inc., 983 F.2d 1039, 25 USPQ2d 1451 (Fed. Cir. 1993); Johnson & Johnson Assoc. v. R.E. Serv., 285 F.3d 1046 (Fed. Cir. 2002).

PROSECUTION HISTORY ESTOPPEL

Under the doctrine of prosecution history estoppel, a patent owner is precluded from asserting a claim scope which would resurrect subject matter surrendered during prosecution of a patent application. The estoppel applies to claim amendments to overcome rejections based on prior art and to arguments submitted to obtain the patent. Hughes Aircraft Co. v. U.S., 717 F.2d 1351, 219 USPQ 473, 481 (Fed. Cir. 1983). In Hughes, the Federal Circuit stated that the extent of the estoppel will vary depending on the nature and purpose of the amendment. However, in Warner-Jenkinson, the Supreme Court partially shut the door on the flexible approach of Hughes by placing the burden on the patent holder to establish that the reason for a claim amendment during prosecution would not give rise to prosecution history estoppel (41 USPQ 2d at 1873). This is the so-called Warner-Jenkinson presumption.

In Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 234 F.3d 558, 56 USPQ2d 1865 (Fed. Cir. 2000) (“Festo VI”) the Federal Circuit expanded upon the Warner-Jenkinson decision. In particular, the Federal Circuit issued the following criteria concerning the application of prosecution history estoppel when a claim is amended:

[1.] ... a narrowing amendment made for any reason related to the statutory requirements for a patent will give rise to prosecution history estoppel with respect to the amended claim element.

Id at 1870.

[2.] Voluntary claim amendments are treated the same as other amendments. Therefore, a voluntary amendment that narrows the scope of a claim for a reason related to the statutory requirements for a patent will give rise to prosecution history estoppel as to the amended claim element.

Id at 1871.

It is noted that the above reference to “the statutory requirements“ in item 1, was stated by the Federal Circuit to refer to 35 U.S.C. §§101, 102, 103 and 112 (See Festo VI, at 56 USPQ2d at 1871.)

In Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 122 S.Ct. 1831 (2002) (“Festo VIII”) the Supreme Court agreed with the Federal Circuit that “a narrowing amendment made to satisfy any requirement of the Patent Act may give rise to an estoppel.” 62 USPQ2d at 1711-1712. However, the Court further stated that even though prosecution history estoppels attaches, it is not a complete bar to the application of the Doctrine of Equivalents. Instead, the Court stated that the reach of prosecution history estoppel “requires an examination of the subject matter surrendered by the narrowing amendment.” 62 USPQ2d at 1712. The Court stated that the patentee bears the burden of showing that the amendment does not surrender the particular equivalent in question. Thus, when a narrowing claim amendment is made, and the patentee does not meet this burden, a court should “presume that the patentee surrendered all subject matter between the broader and the narrower language.” 62 USPQ2d at 1713.

The patentee may rebut the above-described Festo presumption by showing that “at the time of the amendment one skilled in the art could not reasonably be expected to have drafted a claim that would have literally encompassed the alleged equivalent.” 62 USPQ2d at 1714. The Court further provided examples of how the patentee might overcome the presumption. In particular, the Court stated that an amendment could not reasonably be viewed as surrendering a particular equivalent if:

(1) The equivalent was “unforeseeable at the time of the application;” (2) “[T]he rationale underlying the amendment [bears] no more than a tangential relation to the equivalent in question; or” (3) “[T]here may be some other reason suggesting that the patentee could not reasonably be expected to have described the insubstantial substitute in question.”

62 USPQ2d at 1714.

The Federal Circuit reasserted the above-described analysis of the criteria for applying prosecution history estoppel in Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 344 F.3d 1359, 68 USPQ2d 1321 (Fed. Cir. 2003) (en banc) (“Festo IX”)

Other Federal Circuit decisions relating to the issue of prosecution history estoppel include: Texas Instruments, Inc. v. U.S. International Trade Commission, 988 F.2d 1165, 26 USPQ2d 1018 (Fed. Cir. 1993); Lemelson v. General Mills, Inc., 968 F.2d 1202, 23 USPQ2d 1284 (Fed. Cir. 1992); LaBounty Manufacturing, Inc. v. U.S. International Trade Commission, 867 F.2d 1572, 9 USPQ2d 1995 (Fed. Cir. 1989); Prodyne Enterprises, Inc. v. Julie Pomerantz, Inc., 743 F.2d 1581, 223 USPQ 477 (Fed. Cir. 1984); and Bayer Aktiengesellschaft v. Duphar International Research B.V., 738 F.2d 1237, 222 USPQ 649 (Fed. Cir. 1984); Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 493 F.3d 1368 (Fed. Cir. 2007); Amgen Inc. v. Hoechst Marion Roussel, Inc., 457 F.3d 1293 (Fed. Cir. 2006).

HYPOTHETICAL PATENT CLAIM

W ith respect to the patentability of a hypothetical patent claim which literally covers an accused device, the pertinent question is whether a hypothetical patent claim drawn to encompass the accused device would have been allowed by the U.S. Patent and Trademark Office, i.e., whether the hypothetical claim is patentable over the prior art under 35 U.S.C. § 102 and § 103. Wilson, 14 USPQ2d at 1948. Also see Key Manufacturing Group, Inc. v. Microdot Inc., 925 F.2d 1444, 1449, 17 USPQ2d 1806, 1810 (Fed. Cir. 1991) which indicates that the hypothetical claim analysis is not obligatory in every doctrine of equivalents analysis and Insta-Foam Products Inc. v. Universal Foam Systems, Inc., 906 F.2d 698, 15 USPQ2d 1295, 1299 (Fed. Cir. 1990). If it is found that a hypothetical claim corresponding to an independent claim is not patentable over the prior art, then the following question must also be answered. Is a hypothetical claim corresponding to a dependent claim (which depends from the independent claim) patentable over the prior art?

EXAMPLE: The patent claim at issue recites "A golf ball comprising a liquid center and a yellow dimpled cover surrounding said liquid center." The accused device is a golf ball with a liquid center and a violet dimpled cover. The prior art includes white golf balls and red golf balls, both of which have dimpled covers and liquid centers.

In this case, the only word in the claim which does not read on the accused device is the term "yellow." Thus, there is no literal infringement. If the "insubstantial differences" test for infringement under the doctrine of equivalents is met, then the pertinent question is whether a hypothetical patent claim drawn to encompass the accused device would have been allowed by the U.S. Patent and Trademark Office over the prior art. In this case, the hypothetical patent claim would recite "A golf ball comprising a liquid center and a violet dimpled cover surrounding said liquid center." It would then be determined whether this hypothetical claim would have been patentable over the prior art which includes the above-described red and white golf balls. In this case, the court might find that the hypothetical claim is patentable over the prior art since the hypothetical claim recites a color (i.e., violet) on the opposite end of the spectrum from the prior art and is therefore closer to the claimed invention than the prior art.

Taking the Example one step further, if the prior art also included a blue golf ball then it is possible that a court might find that the hypothetical claim was not patentable over the prior art.

The Federal Circuit has indicated that the hypothetical claim approach in Wilson is not the only approach for determining how the prior art restricts the scope of equivalency. Conroy v. Reebok International Ltd., 14 F.3d 1570, 29 USPQ2d 1373 (Fed. Cir. 1994). In this case, the district court compared the prior art with a single element of the accused device to determine how the prior art limited the application of the doctrine of equivalents.

Other Federal Circuit decisions relating to the hypothetical claim issue include: Jurgens v. McKasy, 927 F.2d 1552, 18 USPQ2d 1031, (Fed. Cir. 1991); We Care, Inc. v. Ultra-Mark Int'l Corp., 930 F.2d 1567, 18 USPQ2d 1562, (Fed. Cir. 1991); Marquip, Inc. v. Fosber America, Inc., 198 F.3d 1363 (Fed. Cir. 1999); Streamfeeder, LLC v. Sure-Feed Sys., Inc., 175 F.3d 974 (Fed. Cir. 1999)

* * *

As indicated above, this paper presents a brief overview of the basic issues involved in an infringement analysis. It is not meant to be a comprehensive treatise on infringement. Each patent and accused device to be analyzed will provide their own specific set of facts which will likely require a more detailed look at one or more of the considerations outlined on the attached diagram and possibly a thorough search for specific case law having facts parallel to the situation being analyzed.

Revised 11/01/16