Full opinion text
LONGOBARDI, Chief Judge. This patent infringement suit was brought by American Standard Inc. (“American Standard”) against Pfizer Inc. (“Pfizer”) and Howmedica, Inc. (“Howmed-ica”). Docket Item (“D.I.”) 27. American Standard charges Pfizer with willful and literal infringement of United States Letters Patent No. 3,605,123 (“the ’123 Patent”) and seeks damages, treble damages and attorneys’ fees pursuant to 35 U.S.C. §§ 284, 285. The Defendants deny the allegations of willful and literal infringement and filed a declaratory judgment counterclaim asserting that the ’123 Patent is invalid in light of the prior art and unenforceable due to inequitable conduct before the United States Patent and Trademark Office (“PTO”). D.I. 34. The case was bifurcated such that damages will be the subject of a separate proceeding. This Opinion represents the Court’s findings of fact and conclusions of law. Because the parties raise a large number of separate and distinct issues, the Court’s findings will be integrated and organized by issue. I. BACKGROUND Plaintiff American Standard is a corporation of the State of Delaware and has its principal place of business in New York, New York. Pretrial Order, D.I. 324, ¶ 3B. At the time the suit was filed, Howmedica was a wholly owned subsidiary of Pfizer, which subsequently became a division of Pfizer Hospital Products Group, Inc. and which is also a subsidiary of Defendant Pfizer, Inc. D.I. 324, ¶ 3C. Plaintiff American Standard is the owner of the entire right, title and interest in the ’123 Patent. D.I. 324, ¶ 3D. The 123 Patent issued to Plaintiff on September 21, 1971, based upon an application (Serial No. 820, 184) filed April 29, 1969, naming Henry Hahn as inventor. D.I. 324, ¶ 3E; Plaintiff’s Exhibit (“PX”) 28. The ’123 Patent contains 31 claims and was originally assigned to Melpar, Inc., Hahn’s employer in 1969. When American Standard acquired the Westinghouse Airbrake Company in 1968, it also acquired its partially owned subsidiary, Melpar, Inc. Transcript, D.I. 340, Volume (“Vol.”) G at 1621. American Standard subsequently merged Melpar, Inc. into American Standard in 1969 and assumed the rights to the ’123 Patent when it issued in 1970. PX-30. After American Standard divested itself of the Melpar business in several stages, mostly in 1970, Hahn resigned from Melpar and founded Artech, Inc. (“Artech”), which then acquired the Materials Laboratory assets of Melpar. D.I. 340, Vol. F at 1189, Vol. G at 1623. Hahn is President and Chairman of the Board of Artech and owns 15% of its common stock. D.I. 340, Vol. F at 1189-90. Although it has never manufactured any products under the ’123 Patent, American Standard granted an exclusive license of the ’123 Patent to Artech even before the ’123 Patent was issued on September 21, 1971. D.I. 340, Vol. G at 1629. In 1980, the Bristol-Myers Company (“Bristol-Myers) approached American Standard inquiring about an exclusive license of the ’123 Patent. Id. at 1630-31. On October 7, 1980, American Standard entered into a license agreement with Ar-tech and Bristol-Myers in which Artech gave up its exclusive license in return for a percentage of the royalties that were to be collected from the exclusive license granted to Bristol-Myers and its subsidiary Zimmer Corp. (“Zimmer”). Id. at 1631; DX-275; PX-138. In 1984, Bristol-Myers' exclusive license was changed to a non-exclusive one at the request of American Standard so that it would have the authority to settle several lawsuits brought for infringement of the ’123 Patent. D.I. 340, Vol. G at 1634-36. This Court has jurisdiction over the subject matter of the infringement action pursuant to 28 U.S.C. § 1338(a) and federal jurisdiction over the subject matter of the Defendants’ declaratory judgment counterclaims pursuant to 28 U.S.C. § 2201. D.I. 324, ¶¶ 2, 3A. This Court also has personal jurisdiction over the parties and venue is proper as to the parties under 28 U.S.C. § 1400(b) and 28 U.S.C. § 1391(c). D.I. 324, ¶ 3A. The relevant history of the invention at issue in this case begins with the use of modern biocompatible materials to replace damaged body parts such as hips and knees. Although wood, ivory and noble metals were initially used as prosthetic devices, they were not very useful because of the biological reaction of the body or the inadequate strength of the implant material. D.I. 340, Vol. A at 72. Metals with a smooth surface, such as Vitallium, titanium, tantalum and stainless steel were then used as prosthetic devices. Although each of these metals are biocompatible and have high strength to withstand the normal load bearing stresses of the body, each has also demonstrated a failure to provide a strong union between the prosthetic device itself and the surrounding bone tissue. PX-28, column (“col.”) 2, lines 30-39. Thus, one of the fundamental problems plaguing the development of prosthetic devices or implants for major joints such as the knee or hip is the attachment or fixation of the implant to the adjacent bone. Defendants’ Exhibit (“DX”) 102 at 101; DX-101A at 456; PX-28, col. 1, lines 39-53. The most common problem was the fixation of a prosthesis involving replacement of the upper portion of the femur or thigh bone and of the socket or acetabulum in the pelvis in which the upper ball shaped end of the femur rotates. At the time of the invention of the ’123 Patent, there were three methods used to anchor a prosthetic device to the surrounding bone surface; (1) impaction of the prosthetic stem into the medullary cavity of the bone and held in place by comprehensive residual stress interaction (i.e., press-fit technique), (2) mechanical internal fixation through the use of screws, pins, nails or plates, and (3) methylmethacrylate polymerizing in situ as a cement or filler between the prosthesis and the bone. DX-102 at 101; DX-101A at 456; PX-28, col. 1, lines 33-38; D.I. 340, Vol. A at 71-72, 81, Vol. B at 249-50. Each one of these techniques, however, had problems that prevented the successful skeletal fixation of the implants. For example, prosthetic devices which were implanted by a press-fit technique could loosen when the areas of stress interaction between the implant and the bone were relaxed. DX-102 at 101. Similarly, mechanical devices used to achieve fixation of the prosthetic device often become loose over an extended period of time. Id. Finally, cemented implants proved not so advantageous because they predominantly fail at the interface between the bone and the outer surface of the cement due to a low level of adhesion strength. D.I. 340, Vol. A at 87, 90. If a prosthetic device or bone implant loosens, the results to the patient can be catastrophic, including failure of the implant or of the remaining bone which would require corrective surgery. D.I. 340, Vol. A at 87-88. Thus, scientists in the 1960’s sought to resolve this problem of inadequate fixation of prosthetic devices. Hahn, a metallurgist, sought to overcome the problem of inadequate prosthetic fixation to bone by proposing what he believed was a novel combination of biological and metallurgical concepts and materials. Hahn’s concept was “to stimulate growth of bone tissue into [an] implant (for improved adhesion)” by using plasma flame spray technology to create a porous metal coating or surface layer into which bone tissue would grow and thereby attach the implant to the contacting bone surface. DX-6. The second concept was “the combination of [the plasma flame] sprayed coatings and wrought or cast [metal] substrates in surgical implants.” Id. At trial, Hahn admitted that at the time of his invention it was well known that one could plasma flame spray a porous metal coating on metal and that open pores would promote bone ingrowth. Thus, Hahn testified that his invention was only a “combination of [these] known technologies.” D.I. 340, Vol. G at 1571-72. II. INFRINGEMENT Prior to trial Plaintiff asserted literal infringement by Defendants’ PCA products of claims 1-4, 9-18, 20-22 and 29-31 of the ’123 Patent and infringement under the doctrine of equivalents of the remaining claims. D.I. 324, ¶ 3(F). At trial, however, Plaintiff withdrew sixteen claims and limited its case to proving the literal infringement of claims 1, 2, 10-16, 18, 21, 22 and 29-31 and has expressly not contended infringement by the doctrine of equivalents of those claims. Section 27 of Title 35 of the United States Code provides that “whoever without authority makes, uses or sells any patented invention, within the United States during the term of the patent therefor infringes the patent.” The Federal Circuit has stated that an allegation of literal infringement raises “at least two questions: (1) what is patented, and (2) has what is patented been made, used or sold by another.” Fromson v. Advance Offset Plate, Inc., 720 F.2d 1565, 1569 (Fed.Cir.1983); Phillips Petroleum Co. v. U.S. Steel Corp., 673 F.Supp. 1278, 1344 (D.Del.1987), aff'd, 865 F.2d 1247 (Fed.Cir.1989). In other words, the Court’s infringement analysis follows a two-step process of first construing the language of the asserted claims of the ’123 Patent, and then applying the properly construed claims to Defendants’ accused PCA products to determine if they fall within the scope of the asserted claims. SRI Intern, v. Matsushita Elec. Corp. of America, 775 F.2d 1107, 1118 (Fed.Cir. 1985); Palumbo v. Don-Joy Co., 762 F.2d 969, 974 (Fed.Cir.1985). A. Claim Interpretation In interpreting the disputed claims, the Court should resort to several factors, including (1) the literal language of the claims, (2) the patent specification, (3) prosecution history, and (4) the testimony of experts who can aid in interpreting the asserted claims in the same manner as those skilled in the art. Loctite Corp. v. Ultraseal, Ltd., 781 F.2d 861, 866-67 (Fed. Cir.1985). The threshold requirement in claim construction is an examination of the language of the claims at issue. McGill Inc. v. John Zink Co., 736 F.2d 666, 672 (Fed.Cir.1984). In undertaking such an examination, “the terms of the claims will be given their ordinary meaning, unless it appears that the inventor used them differently.” ZMI Corp. v. Cardiac Resuscitator Corp., 844 F.2d 1576, 1579 (Fed.Cir. 1988) (citing Envirotech Corp. v. Al George, Inc., 730 F.2d 753, 759 (Fed.Cir. 1984)). The claims at issue in this suit are claims 1-2, 10-16, 18, 21-22 and 29-31. In claim 1, Hahn claims: A prosthetic part for use on a bone implant, comprising a strong metal base, said metal base being substantially nontoxic to the biological system of the host into whose bone structure said prosthetic part is to be implanted, and a highly porous metallic region at a surface of said base, said porous region being extremely thin relative to the thickness of said base and extending over substantially that portion of the surface of said base which is to be in contact with the bone structure after implantation. PX-28, col. 5, lines 59-68. Dependent claim 2 adds the requirement that the base is composed of titanium, stainless steel, tantalum or Vitallium. Id., col. 5, lines 69-72. Claim 10 states: A member adapted to promote adherence of bone tissue thereto, said member comprising a highly dense base portion of metal, and a region of high porosity metal coating on the surface of said base portion, said region being thin relative to the thickness of said base portion and arranged for promoting the growth of bone tissue to said member when said member is implanted with said region adjacent living bone tissue. Id., col. 6, lines 21-28. Dependent claim 11 adds the limitation that the porous metal surface constitutes a separate layer bonded to the metal substrate. Id., col. 6, lines 29-31. Dependent claims 12 and 13 require the porous metal surface to extend “over only a part of the surface” of the metal substrate and to be composed of the same metal as the substrate. Id., lines 32-38. Claim 14 specifies that: For use as a permanent bone implant, a structural member including a base composed of metal substantially free of interstices, said member possessing a shape commensurate with bone repair function; and a porous metallic region, thin relative to the thickness of said base located on the surface of said base. Id., col. 6, lines 39-44. Like claims 11-13, dependent claims 15 and 16 merely add the limitations that the porous metal surface covers only a part of the surface of the metal substrate and constitutes a separate layer “overlying and bonded to the surface of said base.” Id., col. 6, lines 45-51. Claim 18 requires “An implant for bone tissue including a base portion of high strength metal and a porous metal layer overlying and bonded to said base portion.” Id., col. 6, lines 54-56. Dependent claims 21 and 22 add the limitations that the porous metal layer and the metal substrate be composed of the same metal material. Id., col. 6, lines 63-68. Claim 29 provides for “[a] metallic bone implant having a porous metallic surface layer.” Id., col. 7, lines 15-16. Dependent claims 30 and 31 merely add the limitations that the porous metal surface layer and the underlying substrate be “chemically, electrochemically, and thermally compatible and non-toxic to said bone” and are composed of essentially the same metal. Id., col. 6, line 17 to col. 7, line 5. 1. Claims Do Not Require Bone Ingrowth Defendants argue that the claims of the ’123 Patent should be interpreted to include the requirement of bone tissue in-growth. Specifically, it is the Defendants’ position that the claims of the ’123 Patent are limited to porous coated implants manufactured and sold only for adhesion by means of bone tissue ingrowth. Howmedi-ca’s PCA products are made by a special sintering technique that creates a porous metal surface with uniform interconnectedness and porosity. In February, 1981, and February, 1984, Howmedica began marketing the PCA knee and hip implants solely for use with bone cement in accordance with FDA regulations, except for investigational devices. D.I. 340, Vol. A at 154, 225, Vol. N at 3317-18, 3336; PX-61. Since bone tissue cannot penetrate the cement material, Defendants contend that their PCA products do not literally infringe the claims of the ’123 Patent. In support of their contention that the claims of the ’123 Patent require bone in-growth, Defendants cite to several references in the specification of the ’123 Patent. For example, in the “Abstract of the Disclosure” of the ’123 Patent, it states: “The porous layer may cover only that part of the surface of the base portion which is to be in contact with the bone tissue after implantation, and permits the growth of bone tissue into the pores.” PX-28, col. 1, lines 19-23. In addition, the “Background of the Invention” emphasizes that the invention is directed to bone ingrowth: “The present invention relates generally to prosthetic parts, and is particularly concerned with improvements in prosthetic devices for use as high strength artificial bone implants adapted to promote a strong union with the bone matter into which such devices are implanted.” Id., col. 1, lines 28-32. The “Summary of Invention” also states: “The principal object of the present invention is to provide a prosthesis of high structural strength with a capability of promoting substantially complete integration with the bone structure in which it is implanted.” Id., col. 2, lines 20-23. Defendants contend that “integration with the bone structure” means “bone ingrowth.” Finally, Defendants point to the “Description of the Preferred Embodiment” and argue that the implantation of porous coated pins in sheep was directed to determine if bone tissue would grow into the pores. Id., col. 4, line 46 to col. 5, line 46. It is an elementary proposition that the property right bestowed by a patent is measured in the first instance by the claims. See A.B. Dick Co. v. Burroughs Corp., 713 F.2d 700, 703 (Fed.Cir.1983) (citing Aro Mfg. Co. v. Convertible Top Co., 365 U.S. 336, 339, 81 S.Ct. 599, 600-01, 5 L.Ed.2d 592 (1961)). Indeed, Title 35, Section 112 provides in pertinent part that “[t]he specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention_” 35 U.S.C. § 112. One commentator has noted: “[t]he function of the claims is twofold: to point out what the invention is in such a way as to distinguish it from the prior art; and to define the scope of protection afforded by the patent.” R. Harmon, Patents and the Federal Circuit at 93 (1988). Thus, it is the claim, not the specification, that measures and defines the metes and bounds of the invention. See, e.g., W.L. Gore & Associates, Inc. v. Garlock, Inc., 721 F.2d 1540, 1548 (Fed.Cir.1983). The significance of the claims in defining an invention was recently expressed by the Federal Circuit in E.I. Du Pont de Nemours & Co. v. Phillips Petro., 849 F.2d 1430, 1433 (Fed.Cir.1988) (quoting Autogiro Company of America v. United States, 181 Ct.Cl. 55, 384 F.2d 391, 395-96 (1967)), when Judge Bissell stated: The claims of the patent provide the concise formal definition of the invention. They are the numbered paragraphs which “particularly [point] out and distinctly [claim] the subject matter which the applicant regards as his invention.” 35 U.S.C. § 112. It is to these wordings that one must look to determine whether there has been infringement. [Footnote omitted]. Courts can neither broaden nor narrow the claims to give the pat-entee something different than what he has set forth. [Footnote omitted]. No matter how great the temptations of fairness or policy making, courts do not rework claims. They only interpret them. In accordance with this instruction, the Federal Circuit has consistently adhered to the proposition that courts “cannot alter what the patentee has chosen to claim as his invention.” SSIH Equipment S.A. v. U.S. Intern. Trade Com’n, 718 F.2d 365, 378 (Fed.Cir.1983) (citing Autogiro, 384 F.2d at 396). It is also well settled that “when claim construction is required, claims are construable ... in light of the patent specification” as well as a number of other factors, such as the prosecution history and expert testimony. SRI, 775 F.2d at 1121; Kalman v. Kimberly-Clark Corp., 713 F.2d 760, 771 (Fed.Cir.1983). Nevertheless, the fact “[t]hat claims are interpreted in light of the specification does not mean that everything expressed in the specification must be read into all the claims.” SRI, 775 F.2d at 1121 (emphasis added). The language in Kalman indicating that claims be interpreted “in light” of their specification to construe their proper meaning only requires the decision maker to consider the specification as one factor in claim interpretation and should “not be confused with adding an extraneous limitation appearing in the specification, which is improper.” E.I. Du Pont de Nemours & Co., 849 F.2d at 1433. By “extraneous”, the Federal Circuit means “a limitation read into a claim from the specification wholly apart from any need to interpret what the patentee meant by particular words or phrases in the claim.” Id. In the present case, there is nothing in the plain language of the claims of the ’123 Patent which suggests that bone ingrowth is required. Instead, the claims of the ’123 Patent reflect Hahn’s conception of combining plasma flame spray technology with a high strength metal base to create a porous metal surface layer so as to achieve fixation by permitting the growth of bone tissue into the pores. D.I. 340, Vol. G. at 1571-72. Indeed, in his “Summary of Invention”, Hahn stated that the principal objective of his invention was to provide a prosthesis with a “capability of promoting substantially complete integration with the bone structure.” PX-28, col. 2, lines 21 to 22 (emphasis added). For example, the broadest claim, claim 29, states “[a] metallic bone implant having a porous metallic surface layer.” PX-28, col. 7, lines 15-16. There is no suggestion in the language of this claim that it requires the function of bone ingrowth as one of its elements. This conclusion is further supported by Hahn’s trial testimony when he stated that there is no requirement of his invention that bone tissue actually grow into the porous metal surface. D.I. 340, Vol. G at 1433-34. Thus, Hahn did not consider his invention to be the discovery that bone tissue can grow into a porous surface. D.I. 340, Vol. G at 1521. Defendants further argue that the prosecution history of the ’123 Patent supports the conclusion that the claimed implant is directed only to an implant into which bone tissue grows. The application of the ’123 Patent as originally filed presented 18 claims that broadly covered a bone implant with any type of porous coating on a metal base so as to promote the growth of bone tissue against and into the pores. PX-15 at 16-19. On November 10, 1970, the Patent Office rejected these 18 claims as being anticipated under 35 U.S.C. § 102 by two patents, U.S. Patent No. 448, 745 (the “Wright Patent”) and a French Patent No. 1,122,634 (the “Steenbrugghe Patent”). Id. at 22. In response, Hahn filed an amended patent application on January 5,1971, in which he amended claims 1, 10 and 14 and added new claims 19-32. Id. at 25-28. In addition, Hahn submitted a I-V2 page statement in which he argued that the Wright and Steenbrugghe Patents “do not disclose a porous metal coating on a strong base, in a bone implant.” Id. at 28-29. Instead, Hahn claimed that these prior patents only: disclose a porous material used as an implant. In the case of Steenbrugghe, the implant is not a bone implant. In the case of Wright, the teaching is of a bone implant, and the coating is porous, but the coating is not metallic. Therefore, the references can only apply to claims which require any type of porous coating on a base. None of the claims as now amended are of this breadth.... The rejected claims are amended to recite that the coating is metallic. Id. at 28. For example, the new claim 30 defines “a metallic implant with a metallic porous surface.” Id. at 29. Thus, the amended claims broadly cover any metal bone implant having a porous metal coating without claiming a functional requirement of bone tissue ingrowth. Kummer Deposition (“Dep.”) DX-978 at 47-50. Defendants contend that the Patent Examiner believed the claims of the ’123 Patent required bone ingrowth by stating in his rejection: “Smith et al. and Jardon are cited to show other devices into which the tissue grows.” PX-15 at 22. This argument is misplaced, however, because the Patent Examiner’s statement does not reject the claims of the ’123 Patent as anticipated or otherwise invalidated by the Smith and Jardon references. Instead, it appears the Patent Examiner cited to these references generally as types of prosthetic devices which permitted tissue to grow into holes. The claims of the ’123 Patent, however, are directed toward the growth of tissue into a porous metal surface layer added to the substrate. Under these circumstances, the Court cannot properly attribute any particular opinion about the scope of the claims to the Patent Examiner with respect to the issue of bone ingrowth. Therefore, the Court finds that the amended claims and the arguments submitted in support thereof demonstrate that Hahn intended his invention to be limited to the combination of a porous metal coating to a solid metal substrate without claiming a limitation that requires bone ingrowth. This interpretation of the scope of the claims is further supported by the language of claim 10, one of the narrowest claims of the ’123 Patent. Claim 10 states, in pertinent part, “[a] member adapted to promote adherence of bone tissue thereto....” PX-28, col. 6, lines 21-22. Although Defendants believe that this phrase should be interpreted to require bone in-growth, claim 10 merely provides that the porous metal surface promotes “adherence” of bone tissue to the metal substrate. This could mean either that bone tissue grow up against the metal substrate or that the porous metal surface contain sufficient porosity so as to allow bone tissue to grow into the pores. Neither interpretation, however, suggests reading into the claim a requirement that bone tissue actually grow into the pores. Even if the meaning of claim 10 could be stretched to include the requirement of growth of bone tissue into the pores, such an interpretation would not apply to other claims in the ’123 Patent because “[w]here some claims are broad and others are narrow, the narrow limitations cannot be read into the broad whether to avoid invalidity or to escape infringement.” Kalman, 713 F.2d at 770. Thus, the Court will not read a functional limitation such as requiring the growth of bone tissue into the pores of the metal surface into the claims of the ’123 Patent in contravention to the express language of the claims. Defendants next argue that the term “bone implant” as used in the claims of the ’123 Patent, such as claim 18, “an implant for bone tissue”, should be interpreted to mean that bone tissue is required to grow into the porous surface layer. The Defendants cannot point to any ambiguity in the term “bone implant” so as to justify reading a limitation contained in the specification into the claim to require bone tissue ingrowth. Plaintiff has introduced evidence, on the other hand, that the term “bone implant” has an accepted meaning in the orthopedic community and refers to “manufactured devices which are intended to be placed in the human body against or within the bone itself.” D.I. 340, Vol. A at 173. A “bone implant” could thus include a prosthetic device in which bone tissue grows either up against or into the device. The Court concludes the term “bone implant” to refer generally to prosthetic devices used for implantation. Thus, the claims of the ’123 Patent are not limited solely to porous coated implants manufactured and sold only for adhesion by bone ingrowth. 2. Claims Require Pore Sizes Ranging From 30 Microns to 200 Microns Defendants next argue that the porous surface of the claims of the ’123 Patent should be interpreted to include surfaces with pores of all sizes. The only claim of the ’123 Patent which expressly refers to the size of the pores is claim 7, which is not an asserted claim. Claim 7 is a narrow claim which is dependent upon claim 1 and provides in pertinent part that “the pore openings at the exterior surface of said layer have widths in the range of about 30 microns to about 200 microns.” PX-28, col. 6, lines 11-14. It is well settled that a limitation contained within a narrow claim cannot be read into a broader claim so as to avoid invalidity. Kalman, 713 F.2d at 770. It is proper, however, “to use the specification to interpret what the patentee meant by a word or phrase in the claim.” E.I. Du Pont de Nemours & Co., 849 F.2d at 1433. Because none of the claims define the term “porous”, an inherently relative term, it is appropriate to interpret the claims in light of the specification to determine the particular meaning of that term. In the present case, the specification defines the relevant pore size of the metal surface. For example, the specification states: “[i]n practice, the pores will range from about 30 microns to about 200 microns wide at the opening, although the range of widths from about 40 microns to about 70 microns appears to be optimum.” PX-28, col. 3, lines 63-66. Since the term “porous” is used similarly in all the independent claims, the Court concludes that the claims of the ’123 Patent require pore size openings that range from 30 microns to about 200 microns. 3. Claims Require Interconnected Pores Defendants next argue that the claims of the ’123 Patent do not require interconnection of the pores. In support of their contention, Defendants point to the express language of various claims of the ’123 Patent such as claim 1 which refers to a “highly porous metallic region”, PX-28, col. 5, line 63, claim 10 which specifies “a region of high porosity metal coating”, id., col. 6, lines 21-22, claim 14 which specifies “a porous metallic region”, id., col. 6, lines 42-43, claim 18 which speaks only of “a porous metal layer”, id., col. 6, line 55, and claim 29 which only describes a “porous metallic surface layer”, id., col. 7, lines 14-15. Although the Defendants point out that there is no express language in the claims which requires interconnected pores, the general term “porous” should be defined in light of the specification. See E.I. Du Pont de Nemours & Co., 849 F.2d at 1433. The specification of the ’123 Patent provides that pores contained within the porous metallic surface are of three types: (1) one type connected to the exterior surface and with other pores “by interior passageways”, (2) a second type with pores “exposed at the exterior surface”, and (3) still other pores “cut off from the surrounding environment.” PX-28, col. 3, lines 55-63. Dr. Ducheyne testified at trial that in order to obtain the “ideal image [for] ... skeletal integration” necessary for fixation, Hahn applied a porous metal surface by a plasma flame spray technique that resulted in some interconnected pores. D.I. 340, Vol. Q at 3841. Dr. Ducheyne also noted that because plasma flame spraying produces a wide variety of possibilities in terms of pores, interconnected pores were not the exclusive type of pores. Id. at 3837-38. Similarly, Defendants’ expert witness, Dr. Burstein, testified at trial that the ’123 Patent revealed “a material that displays some interconnection.” D.I. 340, Vol. N at 3432. Although the term “porous” must then necessarily include some pores which are not interconnected due to the technique of plasma flame spraying, the word includes within its definition some pores which are interconnected. D.I. 340, Vol. Q at 3838. 4. Claims Require a Separate Surface Layer Defendants contend that claims 29-31 do not require the porous metal surface to be a separate entity bonded to the metal substrate. In support of this contention, Defendants point out that the language of claim 18 specifically requires “a porous metal layer overlying and bonded to said base portion”, PX-28, col. 6, lines 55-56, whereas the language used in claim 29 is simply “[a] metallic bone implant having a porous metallic surface layer.” PX-28, col. 7, lines 15-16. Defendants argue that if the term “layer” means a bonded coating in claim 29, then the language “overlying and bonded to said base” in claim 18 is superfluous. This argument, however, elevates form over substance. Defendants’ interpretation of claims 29-31 overlooks the adjective “surface” as it is used in these claims. Since the term “surface” is used to modify the term “layer”, the only reasonable inference is that porous metal is intended to be applied as a separate coating to the metal substrate. If the term “layer” did not refer to a separate porous metal coating to be applied to the metal substrate, then the combined terms of “surface” and “layer” are redundant. The Court refuses to adopt such a narrow characterization of the claims. Although claims 29-31 do not mention the term “coating”, the terms “coating” and “layer” are used interchangeably throughout the ’123 Patent. Although some claims specifically state that the porous metal layer must be bonded to the substrate, see, e.g., claims 3,11 and 16, the omission of the word “bond” from claims 29-31 does not compel the conclusion that the porous metal surface need not be a separate layer. Thus, the Court concludes that claims 29-31 require a metal base with a separate and distinct layer of porous metal. The Court concludes, subject to the interpretation of certain words and phrases, the explanation of which follows, that the scope of the claims has these elements: Claim 1: (a) bone implant, (b) implant constructed of a strong metal base, and (c) with a highly porous metallic region at a surface of said base which is extremely thin relative to the thickness of the base. Under this claim, the inventor has claimed an invention necessarily covering a bone implant. A person skilled in the art at the time of the invention would consider that to mean “manufactured devices which are intended to be placed in the human body against or within the bone itself.” D.I. 340, Vol. A at 173. The strong metal base refers to a device suitable to withstand the loads and stresses associated with the area of the body to be accommodated. The highly porous surface has meaning only in the context of pores having some interconnection and ranging from 30 microns to about 200 microns. The surface layer thinness is described as “extremely thin”, an inherently general term which needs some elaboration. Webster’s Third International Dictionary defines the term thin as “having little extent from one surface to its opposite ... [and] implies comparatively little extension between two surfaces.” Webster’s Third International Dictionary (1981) at 2375. Thus, “thin” can be described as a relative term indicating a general reduction in thickness in comparison to another object. Since resort to the specification reveals that Hahn described by way of example a layer having a thickness up to approximately 0.1 inch with the preferred thickness ranging from .015 inches to .030 inches, PX-28, col. 3, lines 49-53, an “extremely thin” layer must necessarily be less thick than the aforementioned layer which is “thin” in comparison to the metal base. Claim 2: This claim is dependent on claim 1 and, as indicated earlier, adds the requirement that the base be composed of titanium, stainless steel, tantalum or Vital-lium. Claim 10: (a) a device adapted to allow adherence to bone, (b) with a highly dense metal base, and (c) a region of high porosity metal coating that is thin relative to the thickness of the base portion. Under claim 10, the device need not be a structural replacement of the body but any device designed to be anchored by bone. Again, this is a construction within the ordinary meaning of a prosthesis. See, D.I. 340, Vol. A at 173. As previously discussed, the thinness of the porous metal layer may be construed by example from the specification, ie., 0.1 inch or preferably .015 inches to .030 inches. One skilled in the art would have known or could have determined with perfunctory experimentation the thinness required depending upon the purpose of the device and where it was to be used. D.I. 340, Vol. F at 1363-64. Claims 11, 12, 12: As previously discussed, these are claims dependent upon claim 10. Claim 11 adds the limitation that the porous metal surface constitutes a separate layer bonded to the base. Claims 12 and 13 require the porous metal surface to cover “over only a part of the surface” of the base and to be composed of the same metal as the base. PX-28, col. 6, lines 29-38. Claim 14: (a) bone implant, (b) a base substantially free of interstices, and (c) porous metallic region thin relative to thickness of base and located on surface of the base. This claim covers a bone implant or prosthetic device in a shape commensurate with a bone repair function. The base is of a metal composition substantially free of voids or interstices. This claim imposes the additional limitation of using a “dense” metal. See PX-28, col. 2, line 41. That term connotes a solid metal base with a compactness sufficient to exclude voids, cracks or surface pores. The thinness limitation has previously been construed and is adopted here. Claim 15, which is dependent upon claim 14, merely adds the limitation that the porous metal surface should cover only a part of the implant, not its entire surface. PX-28, col. 6, lines 44, 48. Claim 16, also dependent upon claim 14, requires that the porous metal layer be bonded to the bone. PX-28, col. 6, lines 49-51. Claim 18: (a) bone implant, (b) base of high strength metal, and (c) porous metal layer overlying and bonded to the base. Claim 21, which is dependent upon claim 18, adds the limitation that the porous metal layer and the base be composed of the same metal. PX-28, col. 6, lines 63-65. Claim 22, also dependent upon claim 18, adds the requirement that the base be incapable of forming a union with the bone tissue without the porous metal layer. PX-28, col. 6, lines 60-68. Claim 29: (a) metallic bone implant and (b) porous metallic surface layer. The term bone implant has been previously construed and that interpretation applies here. In addition, the term metallic should be limited to those metals described earlier in claim 2. Finally, the porous metallic surface layer, as previously construed, is a separate entity applied to the metallic bone implant. Claim 30, which is dependent upon claim 29, adds the limitation that the bone implant and the porous metallic layer are chemically, electrochemically and thermally compatible and non-toxic to the bone. PX-28, col. 7, line 17 to col. 8, line 2. Claim 31, also dependent on claim 29, adds the limitation that the base and the porous surface layer be composed of the same metal. PX-28, col. 8, lines 3-5. B. Literal Infringement Plaintiff has the burden of proving infringement by a preponderance of the evidence. Envirotech, 730 F.2d at 758; Hughes Aircraft Co. v. United States, 717 F.2d 1351, 1361 (Fed.Cir.1983). Once the claims have been properly construed, the Court must compare the accused devices with the claims of the '123 Patent in order to determine literal infringement. Literal infringement is made out where the accused product falls within the literal scope of the claims of the patent as properly construed. Palumbo, 762 F.2d at 974; Phillips, 673 F.Supp. at 1344. In general, Howmedica’s PCA knee and hip products consist of a separate and distinct porous metal coating with interconnected pores applied to part of a solid metal base comprised of a cast cobalt-chrome-molybdenum alloy. PX-262; PX-268B; PX-84. The porous metal coating of the PCA products “consists of a two layer coating of spherical Vitallium powder which has been sintered in place with 20-30 mesh powder ... to yield an interconnected porosity with metallurgically-bonded powdered particles.” D.I. 340, Yol. L at 2940. The porous coating is approximately 1.55 mm thick measured from the solid core substrate to the more prominent edge of the porous coating. D.I. 324, Admitted Fact, ¶ (H). The porous coating is also comprised of pores ranging in size from 20 microns to 1000 microns with approximately 80% of the pores in excess of 200 microns and an average pore size between 400 to 450 microns. D.I. 340, Vol L at 2944, 2987-88; DX-376 at 2. The Defendants’ PCA products were designed so that fixation could be achieved with or without bone cement. D.I. 324, Admitted Fact, HIT (H), (L). At trial, Dr. Lemons compared Defendants’ PCA revision femoral component, PX-36, with the asserted claims of the ’123 Patent and testified that the accused device “reads on” claims 1-2,10-16, 18, 21-22 and 29-31 of the ’123 Patent. D.I. 340, Vol. D at 718, 721-22, 725-32, 734-35, 738-40. In addition, Dr. Lemons testified that the ace-tabular cup component of the PCA Total Hip, PX-33, the porous hip stem, PX-32, and the other PCA knee components, PX-37, PX-38, PX-39, PX-40, “read on” claims 1, 10 and 14 as that term is used in patent law. Id. Defendants stipulated that Dr. Lemons’ testimony comparing these prostheses against the elements and limitations of claims 2, 10-13, 16-18, 21-22 and 29-31 would be the same testimony previously rendered for the PCA revision femoral component, PX-36. D.I. 340, Vol. D at 804. Defendants have not challenged Dr. Lemons’ testimony of literal infringement of claims 18, 21-22 and 29-31. Independent claim 1 of the ’123 Patent requires that the thickness of the porous coating must be “extremely thin” relative to the thickness of the base, while independent claims 10 and 14 require that the coating must be “thin.” PX-28, col. 3, lines 64-65 and col. 6, line 25. Defendants contend there is no literal infringement of claims 1-2 and 10-16 because Plaintiff has failed to meet its burden of either defining the terms “thin” and “extremely thin” or establishing correspondence between these claims and the accused PCA products. At trial, Dr. Lemons measured the dimensions of the base of the accused devices based on the actual manufacturing blueprints of each of the accused PCA implants. The relative dimensions of coating and base are included in the following table which compares as a ratio the dimension of the base with the admitted thickness of the porous metal coating of “approximately 1.5mm thick measured from the solid core substrate to the more prominent edge of the porous coating away from the substrate.” D.I. 324, ¶ 3(H). Defendants contend that these ratios do not establish that their PCA products meet the limitation's of claims 1-2 and 10-16 because they do not differentiate between “thin” and “extremely thin.” The smallest ratio of the thickness of the base to the porous coating listed in the table is approximately 1 to 1 of the acetabular cup, PX-33, but the range of ratios is 7.67 to 1 around its periphery. The highest ratio involves the PCA hip stem, PX-32, with a ratio of 8.4 to 1 between the base and the coating and 16.1 to 1 when measured across the diameter of the underlying substrate. These ratios corroborate the testimony of Dr. Lemons that each PCA product reads on the limitations contained in claims 1-2 and 10-16 that the porous coating be “thin” or “relatively thin” to the thickness of the base. Hahn also testified at trial that he characterized the terms “thin” and “extremely thin” for Melpar’s outside patent counsel, Mr. Hurvitz: Since the purpose of this coating was to achieve bony ingrowth with [sic without] sacrifice in [the] strength of the implant, the desired attribute would be to have the coating as thin as possible in those structures which are highly stressed, such as a bone stem or a hip stem. I mean, or something which was in — which was loaded heavily in operation in either bending or tension or shear. By this I meant extremely thin; in other words, the coating, itself, is considerably weaker than the forged or cast substrate, and therefore, in a highly stressed part, where the thickness or the cross-section of the part is critical, we wanted it reduced as little as possible, and that’s where I advocated an extremely thin coating. In other parts such as those that are loaded in compression, such as an acetabular cup or the portion that was shown of the milling to be a Lee [sic, knee] joint or other prostheses which contained sections that are not loaded, there, the coating need merely be thin, since it would not detract from the load carrying capacity of that particular implant. D.I. 340, Vol. F at 1363-64. In short, Hahn’s testimony was that highly stressed parts such as a hip stem would have an “extremely thin” coating and parts loaded in compression such as an acetabular cup would have a “thin” coating. For example, the data in the table lists the ratios for the PCA hip stem as 8.4 to 1 and 16.7 to 1 as compared to a ratio of 1 to 1 and 7.67 to 1 of the acetabular cup. Because the testimony establishes that the Defendants’ PCA products, PX-32, PX-34, PX-37, PX-38, PX-39, PX-40, have a porous coating which is “extremely thin” or “thin” as required by the claims at issue, the accused devices literally read on claims 1-2 and 10-16 of the ’123 Patent. Plaintiff’s Exhibit 33 has a porous coating which is thin relative to the base but not extremely thin as required in claims 1 and 2. Nevertheless, it reads on claims 10-16. Defendants contend that the PCA products at issue in this suit are sold only for use with bone cement and do not infringe the claims of the '123 Patent if the Court were to read into the claims a limitation of bone ingrowth. The Defendants further contend that the only products made for adhesion by bone ingrowth were made for clinical investigation in order to obtain FDA approval to market the PCA products after the ’123 Patent expired on September 20, 1988. Therefore, Defendants contend that the only PCA products which could conceivably come within the scope of the claims were those products made and sold for investigational use for adhesion by bone tissue ingrowth. In support of this argument, the Defendants argue that the Federal Circuit’s recent opinion in Eli Lilly and Co. v. Medtronic, Inc., 872 F.2d 402 (Fed.Cir.1989), ruled that the exemption from infringement provided for in 35 U.S.C. § 271(e)(1) applies not only to investigative use of patented drugs for purposes of obtaining FDA approval but also to “medical devices” such as the PCA products. Before Defendants’ argument can be addressed, however, Section 271(e)(1) must be viewed in the proper historical context. In Roche Products v. Bolar Pharmaceutical Co., 733 F.2d 858 (Fed.Cir.1984), the Federal Circuit said there was no experimental use exception to infringement under 35 U.S.C. § 271(a) for a nonlicensee to use a patented drug product before the patent’s expiration. The court concluded that infringement could be found for the investi-gational testing of an infringing medical device even though such testing is required to obtain FDA approval under 21 U.S.C. § 360e. Id. at 864-65. In response, Congress amended 35 U.S.C. § 271(a) by adding Section 271(e)(1) which provides, in pertinent part, that “[i]t shall not be an act of infringement to make, use, or sell a patented invention ... solely for uses reasonably related to the development and submission of information under a Federal law which regulates the manufacture, use, or sale of drugs.” In Eli Lilly, the Federal Circuit concluded “that section 271(e)(1) was added to overrule this court’s decision in Roche.” Eli Lilly, 872 F.2d at 406. The court then held that “section 271(e)(1) allows a party to make, use, or sell any type of ‘patented invention’ [including medical devices] if ‘solely’ for the restricted uses stated therein.” Id. The Federal Circuit made it clear in Eli Lilly that the exemption from patent infringement for investigational devices under Section 271(e)(1) is limited to medical devices used “solely for purposes reasonably related to [the] submission of information” to the FDA. Id. In the present case, however, the evidence demonstrates that Defendants manufactured and marketed the PCA products for the purpose of engaging in the commercial exploitation of the ’123 Patent prior to its expiration. See D.I. 340, Vol. L at 2908; PX-74 at W10774; PX-65 at 6. Defendants admit that Howmedica first marketed its PCA knee products in February, 1981, and first marketed its PCA hip products in February, 1984. D.I. 324, Admitted Fact, 113(G). The Defendants have also admitted that the PCA products “were designed so that fixation could be achieved with or without bone cement.” Id. at 113(L). Since there is no difference in the products designed for “investigational” use and those designed for sale with bone cement only, it stands to reason that the PCA products were not used solely for investigative purposes to submit information to the FDA for approval of the products without the use of bone cement. This conclusion is even more compelling given the fact that the PCA products sold for fixation by bone cement could be and were, in fact, implanted for fixation by tissue ingrowth. D.I. 340, Vol. A at 149. Therefore, it strains the bounds of logic for the Defendants to argue that they should fall under the protective umbrella of Section 271(e)(1) which encourages investigational uses of patented medical devices when they are manufacturing infringing products for commercial purposes. Even if Section 271(e)(1) could be construed to exempt the PCA products made for investigational use with adhesion by bone tissue ingrowth, it would not apply to exempt those PCA products marketed with the labeling instruction “Device is intended for cemented use only”, see, e.g., PX-33, because the Court has previously interpreted the claims of the ’123 Patent as not limited to those implants where fixation is achieved by bone ingrowth. Moreover, it is well settled that the mere labeling of a product to advise customers of an allegedly noninfringing use of the product is insufficient as a matter of law to avoid infringement. Huck Manufacturing Co. v. Textron, Inc., 187 U.S.P.Q. 388, 408 (E.D.Mich. 1975); National Electric Products Corp. v. Circle F. Conduit Co., 62 F.2d 996, 999 (2nd Cir.1933); Sandusky Foundry & Machine Co. v. De Lavaud, 274 F. 607, 610-11 (6th Cir.1921). Furthermore, the FDA has no jurisdiction to prevent a doctor from using an approved drug or device in a manner different from the labeling instructions on the package. United States v. Evers, 453 F.Supp. 1141, 1149 (M.D.Ala. 1978), aff'd 643 F.2d 1043 (5th Cir.1981); see also D.I. 340, Vol. A at 233, Vol. N at 3337. Dr. Mayor testified at trial that the Defendants’ package label would have little effect on the surgeon’s decision on whether to use bone cement or permit fixation of the PCA product by means of bone tissue ingrowth. D.I. 340, Vol. A at 155. Indeed, Dr. Mayor testified that the preferred medical technique today is to implant porous coated prosthetic devices without bone cement. Id. at 149. Since an inventor is entitled to all applications to which his invention can be put to use, including those not mentioned in the specification, the fact the PCA products were capable of being used so that fixation could be achieved with or without bone cement is sufficient for the purpose of showing infringement. D.I. 324, Admitted Fact, 113(L); see B. G. Corporation v. Walter Kidde & Co., 79 F.2d 20, 22 (2nd Cir. 1935); Ansul Company v. Uniroyal, Inc., 448 F.2d 872, 878 (2nd Cir.1971). Thus, as a matter of law, the Defendants cannot shield themselves from liability for infringing the '123 Patent by merely affixing a label to their PCA products admonishing the surgeon to use the PCA product only with bone cement when the PCA product is equally capable of being used without bone cement. C. Doctrine of Reverse Equivalents A determination that the words of a claim literally read on the subject matter of an accused device is but an initial hurdle for the patentee to clear and does not necessarily end the infringement inquiry. Westinghouse v. Boyden Power Brake Co., 170 U.S. 537, 568, 18 S.Ct. 707, 722, 42 L.Ed. 1136 (1898); Autogiro, 384 F.2d at 397; SRI, 775 F.2d at 1118. When the patentee, as here, has met the burden of demonstrating literal infringement, “the accused infringer may undertake the burden of going forward [with evidence] to establish the fact of non-infringement under the reverse doctrine of equivalents.” SRI, 775 F.2d at 1123-24. Under that doctrine, “where a device is so far changed in principle from a patented article that it performs the same or similar function in a substantially different way but nevertheless falls within the literal words of the claim”, infringement liability will not be found. Graver Tank, 339 U.S. at 608-09, 70 S.Ct. at 856; SRI, 775 F.2d at 1123; Phillips, 673 F.Supp. at 1350, aff'd, 865 F.2d 1247. The Federal Circuit has noted, however, that a defense based on the doctrine of reverse equivalents is rarely successful because “products on which patent claims are readable word for word often are in fact the same” in substance as the claimed invention. SRI, 775 F.2d at 1123 n. 19. Consequently, “the defense is seldom raised.” Caterpillar Tractor Co. v. Berco, S.P.A., 714 F.2d 1110, 1112 n. 3 (Fed.Cir. 1983). In the instant case, the Defendants argue that their PCA products do not infringe under the reverse doctrine of equivalents because they do not achieve the same result in the same way as the ’123 Patent. They contend that the sintering technique used to make the PCA products results in a surface structure characterized as a uniform, completely interconnected porous layer which is “completely different” from the type of “structure” obtained by the plasma flame sprayed method disclosed in the ’123 Patent. In support of their argument, Defendants claim that the ’123 Patent yielded a coating which did not have inter-connecting porosity, was not porous and in which bone could not grow to the surface of the substrate. Thus, the Defendants emphasize these characteristics of the sintering technique as demonstrating the substantially different character of their PCA products. In relying upon these differences in the characteristics of the porous metallic coatings, the Defendants have completely misconstrued the inquiry under the reverse doctrine of equivalents. They have not introduced any evidence to demonstrate that the sintering processing technique used in making the PCA products is any different in principle from the claims of the ’123 Patent. In order to determine whether the Defendants’ PCA products are so far changed in principle from the claimed invention as to be noninfringing under the reverse doctrine of equivalents, the Court must first determine the “principle” of Hahn’s invention. SRI, 775 F.2d at 1124; Phillips, 673 F.Supp. at 1354. The invention of the ’123 Patent is the combination for the first time of a porous metal coating bonded to the surface of a metal substrate. D.I. 340, Vol. G at 1571-72. The presence of pores permits the growth of soft or hard tissue into the porous coating for the purpose of achieving “substantially complete integration with the bone structure.” PX-28, col. 2, lines 22-23. The accused PCA product is alleged to be changed by reason of the degree of interconnectedness of the sintered coated surface and the regularity of the average size of the pores which is “completely different” from the structure obtained by the plasma flame sprayed technique which yields a coating that does not have any interconnecting porosity or any pores. Evidence introduced at trial demonstrated, however, that the porous metallic layer produced by the plasma flame sprayed method disclosed in the ’123 Patent contained some interconnected pores and open pores which would permit the growth of soft or hard tissue for bone fixation. For example, the Defendant’s own witness, Dr. Albert Burstein, testified that photographs of the plasma sprayed surface of the pins produced by Mr. Hahn revealed “a material that displays some interconnection or open pore structure.” D.I. 340, Vol. N at 3432. Although the specification of the ’123 Patent indicates that at the exteri- or surface of the plasma coating “some pores [are] cut off from the surrounding environment”, PX-28, col. 3, lines 60-61, the same sentence also states that other pores are “still ... connected by interior passageways.” Id. at lines 62-63. Thus, it cannot be argued by the Defendants that the sintering processing technique employed in making the PCA products is substantially different from the method disclosed in the ’123 Patent because the structure produced by the plasma flame spray method does not produce any interconnected porosity. Furthermore, it is undisputed that the porous coating of the PCA products has the capacity to perform the function of bone fixation “without cement” through tissue ingrowth in exactly the same manner as disclosed in the ’123 Patent. D.I. 324, Admitted Fact, ¶ 3(L). Although the uniform porosity produced by the sintering technique produces a greater degree of interconnectedness, it does not alter the primary function of interconnectedness in accomplishing fixation in a substantially different manner from Hahn’s invention. The fact that the PCA product may be superior to Hahn’s invention because the uniform porosity of the sintered coating enhances fixation by increased pore interconnectedness and by permitting tissue ingrowth to the underlying surface of the metal substrate does not demonstrate that the “principle” of bone fixation through a porous layer attached to a metal substrate as disclosed in the ’123 Patent has been so far changed that the reverse doctrine of equivalents should be applied. Studiengesellschaft Kokle v. Dart Industries, 726 F.2d 724, 728 (Fed.Cir.1984); see also O’Reilly v. Morse, 56 U.S. (15 How.) 62, 123, 14 L.Ed. 601 (1853) (The mere “improvement” or “change in the form” of the patented device which does not essentially vary the device, its operation or organization will not make the new device a new invention.). The Defendants also contend that the plasma flame spray coating was not porous. Presumably, Defendants mean that the PCA products perform the function of bone fixation in a substantially different manner because the '123 Patent does not disclose a range of pore sizes which is sufficient to sustain bone ingrowth. The average size of the pores of the sintered coating range from 400 to 450 microns, whereas the pore size range disclosed in the '123 Patent is “from about 30 microns to about 200 microns wide at the opening, although the range of widths from about 40 microns to about 70 microns appears to be optimum.” PX-28, col. 3, lines 63-66. Professor Williams testified at trial that “functional bone ingrowth” into a porous surface is defined as that which “is going to provide for that fixation between the material and the bone which will be adequate for use in the patient.” D.I. 340, Vol. M at 3043. Although there was inconsistent testimony at trial concerning the minimum pore size that would permit bone ingrowth for functional bone fixation, all of the minimum pore sizes mentioned, 75, 100 and 150 microns, are within the range of about 30 to 200 microns as specified in the ’123 Patent. Although the PCA products have larger pore size openings to permit greater bone ingrowth to achieve better fixation, the PCA products do not present any different means of providing for fixation other than that which is disclosed in the ’123 Patent. Thus, the PCA products produced by the sintered processing technique may represent optimum conditions for achieving bone fixation but such conditions merely reflect changes to a matter of degree. They do not, however, suggest that these changes cause the PCA products to perform the function of fixation in a substantially different way. Since the equivalence of the subsequently developed devices is established by showing only accomplishment of the same result, the sum total of the technological changes effecting the characteristics of the sintered coating does not alter the primary function of bone fixation beyond what the inventor disclosed and, therefore, does not place the accused PCA products beyond the scope of the claims in the ’123 Patent. See, e.g., Texas Instruments v. U.S. Intern. Trade Com’n, 805 F.2d 1558, 1570-71 (Fed.Cir. 1986); Phillips, 673 F.Supp. at 1357. The Court concludes that American Standard has met its burden of proving by a preponderance of the evidence that Defendants’ PCA products infringe claims 1, 2, 10-16, 18, 21, 22, 29-31 of the ’123 Patent. D. Willful Infringment In determining whether an in-fringer acted in bad faith so as to merit treble damages, the Court should consider the “totality of the circumstances.” Shiley, Inc. v. Bentley Laboratories, Inc., 794 F.2d 1561, 1568 (Fed.Cir.1986). Specifically, the Court should consider: (1) whether the infringer deliberately copied the ideas or design of another; (2) whether the infringer, when he knew of the other’s patent protection, investigated the scope of the patent and formed a good-faith belief that it was invalid or that it was not infringed, and (3) the infringer’s behavior as a party to the litigation. Bott v. Four Star Corp., 807 F.2d 1567, 1572 (Fed.Cir.1986). “Willfulness is established only where it is shown that there was a deliberate purpose to infringe, and such a purpose is not found where the validity of the patent and any possible infringement is open to honest doubt.” International Manu