Full opinion text
DECISION AND ORDER STADTMUELLER, District Judge. I. INTRODUCTION This action was filed by American Medical Systems, Inc. (AMS) against Medical Engineering Corporation (MEC) in October 1987. AMS owns, via assignment from William Klatt, U.S. Patent Number 4,597,-765, entitled “Method and Apparatus for Packaging a Fluid Containing Prosthesis.” AMS claims MEC has infringed the patent. MEC has counterclaimed for a declaration of invalidity of the patent, and for relief due to AMS’ alleged breach of certain agreements between the parties. The case was tried to the court, sitting without a jury, for three weeks. Pursuant to Fed. R.Civ.P. 52 the following constitutes the court’s findings of fact and conclusions of law. II. THE PARTIES AND JURISDICTION AMS is a Minnesota corporation with its principal place of business in Minnetonka, Minnesota. Its business is devoted to the research, development, manufacture and sale of penile prosthesis and other medical products of a urological nature. AMS was an independent company until May 1985, when it became a wholly-owned subsidiary of Pfizer Inc. MEC is a Delaware corporation with its principal place of business in Racine, Wisconsin, MEC’s business, too, is devoted to medical products, including mammary and penile prosthesis and urinary stents. Since 1982 MEC has been a wholly-owned subsidiary of the Bristol Meyers-Squibb Corporation. The jurisdiction of the court arises under 28 U.S.C. § 1338(a). Venue is proper in this district pursuant to 28 U.S.C. § 1400(b). III.THE EVOLUTION OF THE PENILE PROSTHESIS Erectile dysfunction affects more than five million men in the United States. The causes range from the physiological to the psychological. Common physical causes include diabetes, neurological or vascular disease, prostate surgery and spinal cord injuries, to name but a few. One of the recognized treatments for erectile dysfunction is the insertion of a penile prosthesis. The first modern penile prosthesis, known as “rods” and “multi-component inflatables,” were developed in the early 1970s and continue to be actively marketed. Both AMS and MEC manufacture the rod prosthesis: respectively, the AMS 600 (Figure A) and the MEC Flexi-Rod. The “rod” type device is generally comprised of cylinders of silicone material, sometimes with a metal wire core. Two cylinders are surgically implanted in the corpora caver-nosa of the penis. The cylinders are always rigid, and at coitus are simply physically manipulated into position. The advantages of this device are that it is simple, inexpensive, easy to implant and essentially free from mechanical failure. On the other hand, the rods permanently rigidized the phallus, resulting in a lack of flaccidity and concomitant problems with concealment. The multi-component inflatable device such as the AMS 700CX (Figure B) consists of a reservoir, at least one pump, and a pair of inflatable cylinders, all connected by tubing. Hence, the product is often referenced as a “three-piece” device. The reservoir is implanted in the patient’s abdominal cavity, the pump in the scrotum, and the pair of cylinders in the corpora cavernosa. In operation, fluid is forced from the reservoir to the cylinders by pumping at the scrotum, which pressurizes and ngidizes the cylinders and phallus. Thereafter, a release valve in the pump can be activated to return the fluid to the reservoir, deflating the cylinders and returning the phallus to a flacid state. The advantages of this device are its superior rigidity, excellent flaccidity and concealment, and the natural look and feel it afforded. However, it requires more invasive surgery, is more expensive, and is more prone to malfunction. Later in the 1970s both AMS and MEC independently began working on a “self-contained” prosthesis. Both designs consisted of a hydraulic, inflatable, fluid-permeable silicone cylinder with the reservoir and pump contained in the cylinder. Both efforts were geared to obtaining the benefits of the three-piece device while avoiding the multiple components and invasive surgery of the three-piece on the one hand and the permanent rigidity of the rods on the other. MEC reached the market first, in October 1984, with a product called “Flexi-Flate.” (Figure C). The prosthesis was shipped sterile but unfilled — that is, without the saline necessary to drive the hydraulic components of the device. This “dry pack” configuration created problems. First, quality control was compromised, since MEC was unable to conduct final functional quality control testing on all the devices. The best that could be done was to test a sample and hope it was representative. There were also problems associated with filling the prosthesis in the operating room. The doctor had to open the patient to determine the appropriate size prosthesis. Then, while the patient was open, the doctor had to fill the two Flexi-Flate cylinders with saline and aspirate them in a procedure that could easily take up to 30 minutes for a surgeon new to the process. The saline had to be specially filtered during filling to avoid the small particulate matter normally found even in the sterile, hospital-grade variety; such particulate can clog the sensitive valves in the cylinders. (Ex. 36 at 7). In addition, the amount of saline to be added to a cylinder was less than a tablespoon, about 8-12 cc, depending on the size of the prosthesis. Precision was critical; underfilling would produce a prosthesis that did not properly rigidize, and overfilling would create a prosthesis which would not deflate properly. The record reflects a number of instances of improper filling during surgeries utilizing the dry-pack prosthesis. (Exs. 55, 58-61, 92-95). IY. KLATT’S INVENTION In the 1970’s AMS began developing its own self-contained penile prosthesis, called the Hydroflex. At least as early as January 1981 AMS knew that having a prefilled and sterile device would be important in the long run. (Ex. 533). By November 1983, AMS was actively seeking a method of providing a prefilled sterile device to the surgeon for surgical implant. (Tr. 1673-74; Ex. 511). The responsibility for solving the problem was assigned to AMS engineer William Klatt. Klatt spoke with the designer of the Hy-droflex device about its design characteristics. He also spoke to the marketing department to find out what kind of package characteristics they would want. He was told they wanted a small, easy to open, two layer package. This packaging would allow a non-sterile nurse to open the non-sterile outer package and present the sterile inner package to a sterile nurse to open in the operating field. Mr. Klatt also spoke with a number of packaging material suppliers, including Kapak Corporation, whose pouches were ultimately used to package the Hydroflex. (Tr. 1675, 1687-1690). In addition, he discussed sterilization methods and sterilization validation with an AMS quality control engineer, John Westrom, and an independent consultant, Skyland Laboratories. (Tr. 1674-76). Mr. Klatt had generally conceived his solution by December 1983: “[PJlace [prefilled Hydroflex] in package, fill package with .9% salt solution, seal package, sterilize.” (Tr. 1678; Ex. 511 at Bates 217). Testing and validation of the solution, however, continued until at least late 1984. (Tr. 1684; Ex. 511). The wet pack configuration had clear advantages over the dry pack. The prosthesis could be accurately filled with particulate-free saline, and the device could be sterilized by the manufacturer before shipment. This guaranteed quality control to the fullest extent possible by eliminating the intervening operating room filling procedure before implantation. As a result, the functional properties of the device would not change from the time of manufacture to the time of implantation. In addition, since there was no filling to be done in the operating room, the surgeon was able to immediately implant the device. The elimination of the intervening step reduced the amount of time the patient was under anesthesia, as well as the overall cost of the surgical procedure. AMS sought to patent the combination of prefilled Hydroflex and packaging created by Mr. Klatt. The invention is fully described in the patent, and discloses how to make and use the invention to obtain its benefits. The patent claims are divided into product claims and method claims. The former, claims 1-12 and 21-24, define the prefilled and presterilized packaged prosthesis. Claim 2 is representative of the product claims: A packaged fluid containing prosthesis adapted to be implanted in a sterile condition, said prosthesis comprising: a prosthetic device, wherein said prosthetic device is an inflatable penile prosthesis, having a closed, permeable housing defining a fluid containing chamber; a sealed, substantially fluid impenetrable enclosure surrounding said housing and defining a liquid retaining space between said enclosure and said housing, said enclosure adapted for separation from said device prior to implantation of said device; and said enclosure containing a liquid in said space with activities that substantially match the activities of the fluid in said chamber such that the mass transfer gradient across the permeable housing is insubstantial. The other product claims add various other limitations to this structure. The method claims, claims 14-15 and 18-20, define the method of making and sterilizing a packaged fluid-containing prosthesis. Claims 18 is representative of the method claims: A method of packaging a fluid containing prosthesis adapted to be implanted in a sterile condition, said method comprising the steps of: filling a closable permeable housing within a prosthetic device with a fluid; enclosing said prosthetic device within an enclosure which contains a liquid with activities that substantially match the activities of the fluid within the housing, thereby rendering insubstantial the mass transfer gradient across the permeable housing; sealing said enclosure about said prosthetic device to define a sealed substantially fluid impenetrable barrier to fluid migration; enclosing said enclosure within an outer bag; and sterilizing said prosthetic device in a liquid filled state within said enclosure and said outer bag. Initially, the PTO examiners found the Klatt invention to be obvious in view of the prior art: The Applicant’s invention differs from Riall in view of Campbell only in the particular device he has chosen to store in the container. In as much as the basic problems of keeping the device wet while avoiding problems of osmosis are addressed and solved in Riall in view of Campbell, the Examiner views the mere substitution of one prosthesis within the package (such as a penile implant) over another as obvious to one of ordinary skill in the art. Ex. 2 at 34. After the rejection, however, the examiners met with Mr. Klatt, his patent attorney, and an AMS official. Id. at 37. The examiners then reversed their earlier finding and held that the Klatt claims distinguished over prior art. The argument that convinced the examiners is summarized in Response A to Paper No. 4: • The prior art fails to teach a packaged fluid containing prosthesis with inter alia a prosthetic device that includes (1) a closed permeable housing defining a fluid containing chamber together with (2) an enclosure containing a liquid with activities that substantially match the activities of the fluid within the chamber such that the mass transfer gradient across the permeable housing is insubstantial, as set forth in pending independent claim 1. In such an arrangement it is possible to precisely engineer or control the volume of fluid in that chamber despite the ability, under atmospheric or other conditions, for the fluid to move through the walls of the housing. This is clearly a problem which was neither recognized or solved by any of the prior art of record. Ex. 2 at 39. The Klatt patent issued on July 1, 1986. (Figure D). V. MEC’s. ACTIVITIES At least as early as April 1984, MEC intended to market a prefilled and sterile Flexi-Flate and (Tr. 1156-57) in early October 1984, MEC assigned the project to senior project engineer Jay Goldberg. (Tr. 1156-57, Ex. 962). Mr. Goldberg’s personal project notebook indicates that the earliest packaging configurations for the pre-filled and sterile Flexi-Flate utilized a rigid, vapor impermeable tube. The earliest configuration was to place the prefilled prosthesis into a tube surrounded by saline of the same osmolarity as that in the device. The tube was then capped. The inner tube was then enclosed in a slightly larger tube or pouch. (Ex. 116 at Bates 101400). In March 1985, Garry Carter, MEC’s vice president of scientific affairs asked Mr. Goldberg to fill out an invention record for this configuration. (Ex. 116; Tr. 272, 277). Nevertheless, as of May 1985, an MEC product definition for the prefilled Flexi-Flate reversed the relationship of the pouch and tube; the prosthesis was to be placed in a saline-filled foil pouch and enclosed in a rigid tube. (Ex. 48 at Bates 105482). Also in May, like many others in the urological products industry, Mr. Goldberg attended the annual American Urological Association (AUA) meeting. This is a significant professional meeting, attended by between one quarter and one half of the urologists in the United States each year. (Tr. 488) As a consequence manufacturers make an effort to promote their newest urological products at the meeting. It was at the May 1985 AUA meeting that AMS officially introduced the wet pack Hydro-flex. (Figure E). This new product, the first prefilled and sterile self-contained prosthesis to reach the market, was received with great interest. The AMS booth received substantial traffic, both from urologists and (not surprisingly) from the competition. (Tr. 312, 488-89). Mr. Goldberg visited the booth. While he was there, he learned that AMS’ packaging concept utilized a saline filled inner pouch containing the prosthesis, surrounded by a larger outer pouch. (Tr. 310-12). He reported his findings to MEC’s R & D and marketing departments upon returning to the office. (Tr. 313). Since AMS had beaten MEC to the punch on prefilling, there was pressure to get the prefilled Flexi-Flate into the market. (Tr. 312). Mr. Goldberg testified that following the AUA meeting, MEC’s efforts intensified: We identified this prefilling as a feature that was necessary that we, you know, wanted to come out with. We saw it introduced and, you know, we — we decided there was another company that has come out with, we need to accelerate our efforts to speed up the project that we had already been working on. (Tr. 402-03). An MEC marketing memo from May 31, 1985 similarly reflects the urgency of the situation: “[W]e must have a prefilled device A.S.A.P.” (Ex. 50 at Bates 106029). For the next several months after the AUA meeting, Mr. Goldberg continued to work on tube packaging concept. (Ex. 963; Tr. 315-16). Tests were run on the various configurations. The results did not prove promising: pouches blew open under the pressure of the autoclave; pouches in tubes developed holes during autoclaving; the tubes leaked due to the inability to get a good ultrasonic weld between tube and cap. (e.g., Ex. 963 at Bates 101416, 101423; Tr. 322). On July 11, 1985 Mr. Goldberg had the good fortune to stumble across Kapak Corporation while searching for autoclavable foil pouches. During his conversation with Kapak’s sales representative, she remarked that the application he had in mind sounded familiar, because a company called AMS was using Kapak’s foil pouches. (Ex. 963 at Bates 101419; Tr. 317). Kapak’s representative sent autoclavable foil samples to Mr. Goldberg. On July 16, Mr. Goldberg received samples of Hydroflex from the marketing department, and he inspected the packaging. (Ex. 963 at Bates 101419; Tr. 318). Mr. Goldberg began to test the double pouch system more intensively. (Ex. 963 at Bates 101419-23). The tube concept continued to experience problems; indeed, throughout this period, and despite repeated attempts, MEC was unable to produce a single successful rigid tube prefilled Flexi-Flate. (Tr. 1253-54). On August 23, Bob Boeck, MEC product manager, decided to go with the double pouch configuration. (Ex. 963 at Bates 101423; Tr. 322-23). The documents of record reflect that the pressure on MEC to get a prefilled product into the market place continued to mount. From an August 11, 1985 capital appropriations request: “Physicians are now starting to turn toward the use of prefilled sterile penile prosthesis rather than the conventional physician-filled implant” (Ex. 63 at 2); from a September 23, 1985 capital appropriations request: “[The purchase of equipment to produce prefilled Flexi-Flate] will put MEC on a more even footing with competitors and will result in a significant increase in projected sales” (Ex. 62); from a February 19, 1986 marketing memo authored by product manager Bob Boeck: In the last several months, I’ve attended at least three key seminars and met with 40-50 urologists (San Francisco, Portland, Los Angeles, Boston, New York, San Antonio). Based on conversations with these doctors, the following is what I see shaping up in the marketplace: 1. Increasing objection to Flexi-Flate not being prefilled. Virtually every doctor who has commented on this aspect of the Flexi-Flate has indicated it adds unnecessarily to O.R. time, which increases cost to the patient. The doctors also see our not having prefilled as an inconvenience on their part and a step which they don’t have to do through if they use the Hydroflex. (Ex. 53). The final product definition for the pre-filled Flexi-Flate, dated May 5, 1986 states that the Flexi-Flate will be shipped in a double foil pouch configuration like Hydro-flex: An implant is filled with saline and placed into the inner pouch, with the tail at the notched end. Fifty (50) ml of saline is added to the pouch and the pouch is sealed. The inner pouch is placed into the outer pouch with the tear notches at opposite ends. .5ml of saline is added to the outer pouch and the pouch is sealed. (Ex. 56 at Bates 105455). VI. MEC ATTEMPTS TO PATENT WET PACK FLEXI-FLATE MEC sought to patent its prefilled and presterilized self-contained device. Mr. Goldberg was asked by Garry Carter, MEC’s vice president for scientific affairs, to submit an invention record for the purpose of filing a patent application for a prefilled Flexi-Flate. (Ex. 116; Tr. 268-70, 272). At the time he signed his invention record, no one questioned that the idea for a prefilled Flexi-Flate was Mr. Goldberg’s. (Tr. 272). The invention record described the many advantages a prefilled Flexi-Flate would have over the unfilled Flexi-Flate being sold at the time. (Ex. 116 at Bates 101401; Tr. 273, 277-82). On February 7, 1986, with full knowledge of AMS’ Hydroflex and its configuration, MEC filed a patent application for a prefilled Flexi-Flate in the name of Jay Goldberg. (Ex. 117; Tr. 415-16). The Goldberg application was assigned to MEC. (Tr. 392). The application describes the significant advantages of the prefilled device over an unfilled device. (Tr. 342-44). When Mr. Goldberg signed the application, he believed that he was the original and sole inventor and he was not aware of any material prior art. (Ex. 117; Tr. 339-42). Mr. Goldberg further believed at the time he filed his patent application that the combination of a double pouch and a pre-filled self-contained inflatable penile prosthesis, with fluid in the pouch to keep fluid from coming out of the device, was new. (Tr. 396-97). When MEC’s attorney prepared the application, it was reviewed by at least Mr. Goldberg, and MEC’s attorney expected Mr. Goldberg to sign and the PTO to examine the application with the claims as filed. (Tr. 1373, 1376-80). MEC and its attorneys fully participated in the selection of the prior art to be disclosed to the PTO. (Tr. 355-56). MEC’s attorney was experienced and familiar with the prior art. (Tr. 1368-69, 1380-82). MEC has suggested that the Goldberg patent application was limited to the use of a rigid tube or “nonexpandable” outer enclosure, but this argument is unconvincing. The Goldberg application plainly teaches that a flexible double pouch can be used. (Tr. 348-53, 387-91). Both Mr. Goldberg and Mr. Carter, who was also involved in the Goldberg application, each admitted that claim 3 of the Goldberg application would cover AMS’ Hydroflex. (Tr. 352-53, 414). The PTO issued a restriction on MEC’s application, requiring the attorney of record, Mr. Kryshak, to elect which invention he wished to pursue. He elected to proceed with claims 1, 2, 11 and 12. In February 1987, the PTO issued its first office action, which rejected claims 1 and 2 “as being unpatentable over Klatt in view of Lloyd.” Claims 11 and 12 were rejected “as being clearly anticipated by Klatt.” (Ex. 117 at 49). Thereafter, the application was abandoned. (Tr. 1387-88). VII. VALIDITY OF THE KLATT PATENT A patent shall be presumed valid, and each claim shall be presumed valid independently of the other claims. 35 U.S.C. § 282. The burden is on the party asserting invalidity to prove it with facts supported by clear and convincing evidence. Loctite Corp. v. Ultraseal Ltd., 781 F.2d 861, 872 (Fed.Cir.1985). The presumption of validity is premised on the expertise possessed by the Patent and Trademark Office interpreting the references and having familiarity with the level of ordinary skill in the art. Bausch & Lomb, Inc. v. Barnes-Hind/Hydrocurve, Inc., 796 F.2d 443, 447 (Fed.Cir.1986) cert. denied, 484 U.S. 823, 108 S.Ct. 85, 98 L.Ed.2d 47 (1987). The deference accorded to the PTO’s expertise is heightened where the prior art before the court is the same as that before the PTO. Id. MEC contests the presumptive validity of the patent on the grounds that the invention was obvious from the prior art. 35 U.S.C. § 103. The ultimate conclusion of obviousness is one of law, but the conclusion is based on the factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 17, 86 S.Ct. 684, 693, 15 L.Ed.2d 545 (1966): 1) the scope and content of the prior art; 2) the difference between the prior art and the claims at issue; 3) the level of ordinary skill in the pertinent art at the time the invention was made; and 4) the objective evidence of nonobviousness, such as commercial success, satisfaction of a long-felt need, failure of others, recognition by the industry, and copying. As the court embarks upon its obviousness inquiry, it is instructive to keep a recent caution by the Federal Circuit in mind: The obviousness standard, while easy to expound, is sometimes difficult to apply. It requires the decisionmaker to return to the time the invention was made. The invention must be viewed not with the blueprint drawn by the inventor, but in the state of the art that existed at the time.... That which may be made clear and thus ‘obvious’ to a court, with the invention fully diagrammed and aided by experts in the field, may have been a breakthrough of substantial dimension when first unveiled. Uniroyal, Inc. v. Rudkin-Wiley Corp., 837 F.2d 1044, 1050-51 (Fed.Cir.1988). A. Scope and Content of the Prior Art The scope of the prior art is that art which is reasonably pertinent to the particular problem with which the inventor was involved. Hewlett-Packard Co. v. Bausch & Lomb, Inc., 722 F.Supp. 595, 605 (N.D.Cal.1989) citing In re Deminski, 796 F.2d 436 (Fed.Cir.1986). The scope of the prior art would include methods and materials used in medical and food packaging. MEC’s expert on the question of obviousness, Dr. James Goff, stated that he found the following prior art to be the most relevant to whether the Klatt patent was invalid for obviousness (Tr. 1939-40): 1) the Banko patent (Ex. 854) combined with the Mazzocco patent (Ex. 889); 2) the Naficy patent (Ex. 751); 3) the “suture” patents, Riall (Ex. 3) and Rynkiewicz (Ex. 507); 4) the canning and pickling of food (Tr. 1939-40); 5) Dr. Austad’s patent, publication (Ex. 899), and experiments with tissue ex-panders. The Banko patent teaches a method and apparatus for implanting a fluid-filled replacement lens in the human eye. The lens is to be made of a deformable “suitable plastic material” such as for example used in soft contact lenses; it is not apparent whether this material is permeable or not. The lens may be filled with a sterile solution, gelatin, or plain or Ringers saline solution. (Ex. 854 at col. 2). Banko does not teach that the implant is to prefilled and presterilized by the manufacturer. (Tr. 1933). The Mazzocco patent teaches, among other things, an improved method of packaging an intraocular lens such that the optical parameters of the lens could be viewed from outside the bottle. A screw top bottle made of glass, stainless steel, titanium, or polymeric material such as silicone rubber is used; it is filled with a “suitable fluid” such as saline, distilled water, or alcohol. The lens is suspended from a holder affixed to the cap. The result is designed to be autoclavable. (Ex. 889 at col. 4 lines 25-28, col. 6 lines 45-65, and col. 7 lines 29-35). The Naficy patent is formally titled “Breast Prosthesis with a Biologically Ab-sorbable Outer Container.” As its name suggests, the patent teaches a breast prosthesis comprised of an inner core of biologically acceptable material surrounded by silicone rubber sac in the preferred embodiment. The inner core is in turn surrounded by an outer sac made of biologically ab-sorbable material; there is saline between the inner and outer membranes. The whole unit is implanted, and with time the outer membrane is absorbed into the body. For present purposes, there is no material differences between the two suture patents. (Tr. 1967-68). Mr. Klatt cited the Riall patent in his application. In Riall, the sutures are packaged in an inner envelope which is enclosed in two more envelopes, each envelope nested inside the other. The interior envelope may contain the sutures dry or in a conditioning liquid. Sutures which require a conditioning liquid are packed in ethyl alcohol, or a mixture of ethyl alcohol, isopropyl alcohol, and water, or some other conventional conditioning liquid. In the Rynkiewitz patent, the suture is packed in a packet containing conditioning liquid such as methanol or ethanol. This packet is in turn packaged in another, larger packet. Dr. Goff also claimed that he found the canning and pickling of food to be relevant. He testified that in canning, the food item — he used the example of green beans — is blanched in hot salt water. This process purges the gases from the bean, densifies it, and fills the bean with blanching fluid. The beans are then put in a can, the headspace is purged to remove excess air, and a lid is put on. The can is then placed in a pressure vessel and subjected to a steam cooking process. (Tr. 1864-65). Dr. Goff stated that the scientific principle involved in the blanching process was osmosis. Id. Dr. Goff also testified that he found the patent and work of Dr. Austad to be relevant. Dr. Austad has a patented tissue expander which is of record in this case. (Ex. 503). The patent teaches a surgically implantable device for expanding skin and mucous tissue. The device involves the use of a partially collapsed sealed envelope formed from a material which is permeable to extracellular body fluid, such as silicone. The envelope contains a material which establishes an osmotic potential across the envelope wall, such as dry sodium chloride. Body fluid crosses the membrane to fill the envelope. As the envelope fills it expands the adjacent tissue. There is no disclosure in the patent or Dr. Austad’s publication (Ex. 899) of preparing or shipping prefilled implants which are then implanted in the body. Dr. Goff also found Dr. Austad’s post-experiment storage of tissue expanders to be relevant. Basically, Dr. Austad testified that he would store the filled tissue expan-ders in jars of saline. For the most part, the salt concentration in the saline initially differed from that in the tissue expander. (Tr. 1585). However, Dr. Austad also testified that he performed one experiment where the tissue expander had much more than an isotonic amount of saline inside. To store these implants, saline plus additional sodium chloride crystals were poured into the jar; as a result, the salt concentration inside the implant and outside the implant was the same. (Tr. 1585-86). Dr. Austad also testified that his experiments were “essentially” accessible to the public. (Tr. 1588). He said various people including students, surgeons, drug representatives and the like passed through his laboratory. But it became clear to the court on cross examination that while various persons may have entered Dr. Austad’s lab, the concept of how the filled tissue expanders were stored was not public. For one thing, persons having access to the lab would not know the import of the jars until someone explained it to them. (Tr. 1624). Certainly, Dr. Austad did not go out of his way to point it out to visitors. Indeed, Dr. Austad stated that he could not remember anybody inquiring into the specifics of this storage method. (Tr. 1623). Consequently, the court does not find Dr. Austad’s experiments to be prior art for purposes of 35 U.S.C. § 102. The court observes that even if it were to consider the jars to be prior art, there would be a number of reasons why they do not render Klatt’s invention obvious to a person of ordinary skill in the art. First, the jar experiment is not a packaged prosthetic device intended to be implanted. The devices were in jars for testing purposes, not as future implants. Second, the only sterilization Dr. Austad recalled involved sterilizing explanted devices, not devices filled and intended for implantation. In addition, the Austad implants were sterilized in open beakers, not the jars or any other “package.” (Tr. 1592, 1609-10). In any event, the jars could not maintain sterility, even were it possible to sterilize them. Third, except for one experiment, Dr. Aus-tad frankly admitted that in his “jar experiments”, he did not achieve any osmotic balance between the devices and liquid in which they were placed without an initial mass transfer gradient between the device and the liquid in the jar. B. Level of Ordinary Skill in the Art Factors that may be considered in determining level of ordinary skill in the art include: 1) the education level of the inventor; 2) type of problems encountered in the art; 3) prior art solutions to those problems; 4) rapidity with which innovations are made; 5) sophistication of the technology; and 6) educational level of active workers in the field. Orthopedic Equipment Co., Inc. v. All Orthopedic Appliances, Inc., 707 F.2d 1376, 1381-82 (Fed.Cir.1983). Not all such factors are present in every case, and one or more may predominate in a particular case. A second formulation of the person of average skill in the art: The person of average skill in the art, under sec. 103, who is the patent law equivalent of the reasonable man in tort law, is neither a genius nor an expert, and he is not expected to think entirely in terms of theoretical, physical principles, but is much more likely to be motivated by more mundane considerations, such as the practical functional use of prior art devices. Ciba-Geigy, Ltd. v. Tenatek, 202 USPQ 669, 674 (N.D.Miss.1978). Regardless of the formulation used, the important consideration lies in the need to adhere to the statute. The court must hold that an invention would or would not have been obvious, as a whole, when it was made, to a person of “ordinary skill in the art” — not to the judge, or to a layman, or to those skilled in remote arts, or to geniuses in the art at hand. Environmental Designs v. Union Oil Co. of California, 713 F.2d 693 (Fed.Cir.1983). The relevant time frame is 1983-84. The court finds the testimony of Dr. Goff and Donald Barcan relevant to the resolution of this issue. Dr. Goff testified that the person with ordinary skill in the art would have a technical degree and two or three years of experience in the design of packages for medical devices. (Tr. 1861). On cross examination, he admitted that the most salient training for the packaging field occurs on the job. Similarly, he stated he would not be surprised if there were persons involved in designing packages who had no college education. (Tr. 2021). Donald Barcan is a packaging engineer called to testify by AMS. He testified that in the 1960s — the infancy of sterile medical device packaging technology — the skill level required to package medical devices was low. “It might have been a glass syringe, for example, and it went into a box and that box might have been wrapped with tissue.” (Tr. 2289). Not surprisingly, persons assigned to package devices usually had no more than a high school education. As the technology associated with medical device packaging became more sophisticated, these persons were not replaced. However, the technical education of incoming packaging personnel began to increase, and through attrition, the educational training of persons skilled in the art began to change. By 1983-84, approximately one third of persons skilled in the art had college degrees. (Tr. 2237-40). The court also observes that while both William Klatt and Jay Goldberg had technical degrees, neither had any prior experiences in packaging medical devices. Given the testimony, the court finds that the person of ordinary skill in the art in 1983-84 would have either had a college degree and several years of experience in the medical device packaging field, or would have had no college degree but would have had five to fifteen years experience in the medical device packaging field. C. Differences Between the Prior Art and the Claims at Issue Mr. Klatt’s invention involves a packaged fluid-filled device containing a defined amount of fluid in a semi-permeable housing, and methods of packaging and sterilizing it. The testimony did not disclose that the concept of prefilling and presterilizing a device by the manufacturer existed in the prior art. For example, Banko does not establish this. Professor Goff admitted that Banko does not teach that the lens is to be packaged prefilled and presterilized at the manufacturer. (Tr. 1932-33; see also 2259). Nor does the combination of Banko combined with Mazzocco establish this. Neither, according to Dr. Goff, does Naficy teach this particular concept. (Tr. 1934). And the court is simply not convinced that Dr. Austad’s patent or jar experiments establishes this. His patent indicates that the implants were intended to be implanted dry; the concept behind his tissue expander was to allow the filling of the device to occur gradually, making the stretching of the tissue less painful. His jar experiments, to the extent they can be considered prior art, were with explanted devices which had filled during their stay in the body of an animal; they were not intended to be reimplanted in that form. The court also finds there is no prior art showing any packaged medical device containing a defined amount of fluid in a permeable membrane. (Tr. 2026). Dr. Goff admitted that Mr. Klatt designed a product that was filled with a precise amount of fluid by the manufacturer. (Tr. 1936-37). It was then packaged and the package was sterilized. (Id.). The critical amount of fluid in the device survived the packaging and sterilization. (Id.). Thereafter, the critical amount of fluid and sterility remained inviolate and survived handling, transport, and lengthy storage so that it was “ready-to-go” during surgery. (Id.). And this, Dr. Goff admitted, “no one had ever done before.” (Tr. 1937). Similarly, there is no prior art showing the use of osmotic principles for purposes of packaging and sterilizing any product, much less a medical device. (Tr. 2254). Sutures, as well as packaged bandages, sponges, and soft optical lenses, simply absorb the liquid in the package until they are saturated. There is no need or ability to control the amount of fluid in the materials. (Tr. 1970). In short, these patents merely provide a mechanism by which these items can be kept moist. On the other hand, the Klatt invention involves a device with a critical amount of fluid in a semi-permeable housing, where the fill volume is maintained by controlling the osmo-lality of the solution inside and outside the device. Analogously, the suture packages do not need to be completely filled with fluid because they are conditioning liquids. Klatt requires substantially complete filling, because air in the enclosure may cause bubbles to permeate the device, causing it to lose critical filling volume. (Tr. 1972-73). If food packaging and canning is considered prior art, it is no more pertinent than the prior art found in the Campbell patent (Ex. 7) or the Riall patent (Ex. 3) which were considered by the PTO. The canning process described by Dr. Goff included “blanching” the vegetable, placing it in a can, and then closing it. (Tr. 1944-49). In the can, however, the vegetable is saturated with the filling solution and absorbs the fluid around it. There is no way to control how much liquid the food absorbs. (Tr. 1948-53). Finally, Mr. Klatt’s invention was the first time an autoclave process was used with a packaged penile prosthesis. (Tr. 1956). D. Secondary Considerations It is jurisprudentially inappropriate to disregard any relevant evidence on any issue in any case, patent cases included. Thus evidence rising out of the “secondary considerations” must always be considered when present, before any determination on the obviousness question is rendered. It is to be considered as part of all the evidence, not just when the court remains in doubt after reviewing the art. Stratoflex, Inc. v. Aeroquip Corp., 713 F.2d 1530, 1538-39 (Fed.Cir.1983). Evidence of secondary considerations may establish that an invention appearing to have been obvious in light of the prior art was not. Id. The principal secondary considerations which support findings of non-obviousness are: a) commercial success; b) long-felt but unsolved need; c) failure of others; and d) copying of the claimed invention. 1.Commercial Success The court finds the Hydroflex was a commercially successful product. From its introduction at the May 1985 AUA meeting, the product enjoyed very good sales, though beginning in 1987 demand for the product has steadily declined. The evidence reflects that in 1985 AMS sold 3,336 Hydroflex units for total dollar sales of $7,665,142.00; in 1986 AMS sold 7,698 Hy-droflex units for total dollar sales of $17,-211,040.00; and in 1987 AMS sold 4,809 Hydroflex units for total dollar sales of $13,105,847.00. (Ex. 107). 2.Longfelt But Unsolved Need Against the backdrop of other patent cases the court has examined, the length of time the urological products industry went without a prefilled and sterile packaged penile prosthesis is not especially long. See e.g. 2 D. Chisum, Patents, sec. 5.05[1] at 5-398 to 5-399. Approximately eight months elapsed between MEC’s introduction of its dry pack Flexi-Flate (October 1984) and AMS’s introduction of the Hydro-flex (May 1985). There is no evidence of any other company’s efforts to prefill a penile prosthesis. 3.Failure of Others, and Copying During the time Mr. Klatt was working on the prefilled Hydroflex, MEC was also working on its prefilled product but without success. Mr. Goldberg then saw the Klatt invention the 1985 AUA meeting and began considering the double pouch system more seriously. In the court’s opinion it was no mere coincidence that MEC began to work intensively with the double pouch system shortly after seeing Klatt’s invention at the AUA. The court further observes that, as elaborated at length above, MEC attempted to patent a prefilled product which falls literally within the scope of claims 1-12, 14-15, 18-20, and 20-24 of the Klatt patent. E. Conclusion on Obviousness Mr. Klatt’s invention is a packaged penile prosthesis and method composed of, respectively, multiple components and multiple steps. All these interact to provide a particular kind of surgical prosthesis with suitable intraoperative characteristics. The invention as a whole is that product, with its packaged form, and its advantages, benefits and properties. It is the combination which is novel and is the subject of the claims of the Klatt patent. (Tr. 1081). That all elements of an invention may have been old is not unusual, and indeed, irrelevant. Virtually all inventions are combinations and virtually all are combinations of old elements. A court must consider what the prior art as a whole would have suggested to one skilled in the art. Environmental Designs, 713 F.2d at 698. The court is unable to accept MEC’s contention that the claims of the Klatt patent would have been obvious to a person of ordinary skill in the art at the time of Klatt’s invention. It appears to the court that MEC has used the Klatt patent as a roadmap for finding prior art, and had then attempted to combine that prior art with the hindsight afforded by it knowledge of Mr. Klatt’s invention; this appeared especially to be true in the case of Dr. Goff’s testimony. For example, MEC’s main argument is that Klatt is rendered obvious by combining Banko and Mazzocco. (Tr. 1975). Yet there is nothing in the prior art of record which would invite or suggest to a person of ordinary skill in the art that the two references be combined. That combination can only be made by hindsight reconstruction using Klatt as a roadmap. The only reason Dr. Goff could give for attempting to combine Banko with Mazzocco was a two pronged “leap of faith” (Tr. 2000) that: 1) Banko would be filled at the manufacturer and be shipped prefilled and sterile; and 2) Mazzocco was the only way of doing it. However, Banko does not disclose how or where his lens is filled or how it is implanted. (Tr. 2246). Even Dr. Goff admitted this. (Tr. 1989). Because there is no suggestion in the art that a Banko lens would be shipped prefilled, there is no incentive or motivation for anyone to combine it with a fluid-filled packaging system such as Moz-zocco. It also appears that there is a reason why those with ordinary skill in the art would not combine Banko and Mozzocco, namely that the Banko and Mozzocco lenses function differently. Mozzocco’s lenses do not change shape in the eye. (Tr. 1985; 2247-48). It maintains the same optical properties at all times. On the other hand, the Banko lens is designed to be sutured to muscles in the eye. Then, as the muscles moved, the lens would change its shape and optical properties. (Ex. 854, col. 3; Tr. 1984, 2247-48). The differences are relevant because the point of Mozzocco is to provide a container and fixture whereby the optical properties of a fixed lens can be measured. (Tr. 2247-48; 2261). The Ban-ko lens is not of a type for which the Mozzocco container was designed; the optical properties of the Banko lens are not fixed and change when sutured to the eye muscles. Consequently, there is no motivation for one skilled in the art to combine the two patents. MEC has not shown anything in the prior art that suggests the particular combination of elements needed to produce Klatt’s invention. An invention must be viewed as a whole, and MEC’s prior art does not suggest in any way or motivate one skilled in the art to make the Klatt invention as a whole. After becoming aware of the issuance of the Klatt patent, MEC engaged in numerous world-wide searches. (Ex. 118). Yet despite all of this extensive searching, MEC has not found any references which describe the unique combination claimed in the Klatt patent. MEC plainly believed that this subject matter was new and non-obvious as evidenced by the filing of its own patent application on the subject matter and failing to cite any of the prior art upon which it now relies to invalidate the Klatt patent. VIII. DAMAGES Since the court has determined that the Klatt patent is not invalid for obviousness, and MEC has stipulated that its Flexi-Flate prosthesis would infringe upon such a finding, the court must consider the amount of damages to which AMS is entitled. AMS claims that it is entitled to lost profits for the period of July 1, 1986 (the date the Klatt patent issued) through December 1987 (MEC’s noninfringing “vacuum pack” Flexi-Flate entered the market in January 1988) because, but for MEC’s infringement, AMS would have made the sales that were made by MEC for its wet pack Flexi-Flate. From January 1988 AMS claims a reasonable royalty, since during this period MEC was principally selling the “vacuum pack” Flexi-Flate (which AMS no longer accuses of infringement), but also continued shipping its remaining inventory of the wet pack Flexi-Flates. The applicable statutory authority governing the amount of damages is 35 USC 284, which provides in pertinent part: Upon finding for the claimant the court shall award the claimant damages adequate to compensate for the infringement, but in no event less than a reasonable royalty for the use made of the invention by the infringer, together with interest and costs as fixed by the court. The United States Supreme Court, in interpreting this statute, has defined damages as “compensation for the pecuniary loss the patent owner suffered from the infringement, without regard to the question whether the defendant has gained or lost by its unlawful acts.” Aro Mfg. Co. v. Convertible Top Replacement Co., 377 U.S. 476, 507, 84 S.Ct. 1526, 1543, 12 L.Ed.2d 457 (1984). There are two different approaches toward determining the measure of damages in patent infringement cases. Hartness Int’l v. Simplimatic Engineering Co., 819 F.2d 1100, 1112 (Fed.Cir.1987). The first approach, the lost profits method, is used when the record permits an accurate determination of the patentee’s loss. Hanson v. Alpine Valley Ski Area, Inc., 718 F.2d 1075, 1078 (Fed.Cir.1983). The second approach, employed when actual lost profits cannot be determined, is to award damages on the basis of a reasonable royalty. Id. A. Lost Profits Pursuant to 35 U.S.C. § 284, “[t]he general rule for determining the actual damages to a patentee that is itself producing the patented item is to determine the sales and profits lost to the patentee because of infringement.” Del Mar Avionics v. Quinton Instrument Co., 836 F.2d 1320, 1326 (Fed.Cir.1987). To obtain lost profits, a patent owner must prove causation; that is, that “ ‘but for’ the infringement, the patent owner would have made the sales the infringer made.” Lam, Inc. v. Johns-Manville Corp., 718 F.2d 1056, 1065 (Fed.Cir.1983); Bio-Rad Laboratories, Inc. v. Nicolet Instrument Corp., 739 F.2d 604, 616 (Fed.Cir.) cert. denied, 469 U.S. 1038, 105 S.Ct. 516, 83 L.Ed.2d 405 (1984). “In proving his damages, the patent owner’s burden of proof is not an absolute one, but rather a burden of reasonable probability.” Lam, 718 F.2d at 1065. The patent owner need only prove that there is a reasonable probability he would have made the infringing sales. Paper Converting Machine Co. v. Magna-Graphics Corp., 745 F.2d 11, 21 (Fed.Cir.1984). “The determination of damages is not an exact science and ‘the amount need not be proven with unerring precision.’ The trial court is required to approximate, if necessary, the amount to which the patent owner is entitled.” Del Mar Avionics, 836 F.2d at 1327. In addition, “[t]he patentee is not obligated to negate every possibility that a purchaser might not have bought the patentee’s product instead of the infringing one, or might have foregone the purchase altogether.” Id. at 1326; Datascope Corp. v. SMEC, Inc., 879 F.2d 820, 826 (Fed.Cir.1989). A patent owner may obtain lost profits by meeting the standard set forth in Panduit Corp. v. Stahlin Bros. Fibre Works, Inc., 575 F.2d 1152 (6th Cir.1978): To obtain as damages the profits on sales he would have made absent infringement, i.e., the sales made by the infringer, a patent owner must prove: (1) demand for the patented product, (2) absence of acceptable noninfringing substitutes, (3) his manufacturing and marketing capability to exploit the demand, and (4) the amount of profit he would have made. Id. at 1156. A patentee is not entitled to lost profits if it fails to establish any of the above requirements. Smithkline Diagnostics v. Helena Laboratories, 926 F.2d 1161, 1165 (Fed.Cir.1991). The patent owner must convince the court that it has met each of these elements to a reasonable probability. MEC does not dispute that there was a demand for the patented product (although it argues that demand did not result from the patent). The court independently finds that there was demand for the patented product, and that demand resulted in substantial part from the characteristics of the patented product. (Tr. Bible, see also MEC Response para. 58). Similarly, MEC does not dispute that AMS had the ability to exploit the demand for the product. The court similarly finds that AMS had the ability to exploit demand for the product. (Tr. 816; Ex. 106). Central to whether there were “acceptable noninfringing substitutes” for the Hy-droflex is the definition of that term. In the recent case Kaufman Co., Inc. v. Lantech, Inc., 926 F.2d 1136 (Fed.Cir.1991), the Federal Circuit offered the following guidelines for determining if any exist. To be deemed acceptable, the alleged acceptable noninfringing substitute must not have a disparately higher price than or possess characteristics significantly different from the patented product. “A product lacking the advantages of that patented can hardly be termed a substitute acceptable to the customer who wants those advantages.” Id. at 1142-43 (emphasis in original), quoting TWM Mfg. Co., Inc. v. Dura Corp., 789 F.2d 895, 901 (Fed.Cir.1986). Nevertheless, “if the realities of the market are that others would likely have captured sales made by the infringer, despite a difference in the products, it follows that the ‘but for’ test is not met.” SmithKIine Diagnostics v. Helena Laboratories, 926 F.2d 1161, 1166 (Fed.Cir.1991). MEC has urged that the court must consider all impotence treatments, including drug therapy, rods, and multi-component inflatables as acceptable noninfringing substitutes for the Hydroflex. Yet the evidence clearly convinces the court otherwise. The salient characteristics of the Hydroflex are that it provided good flaccidity and rigidity without the more invasive surgery necessary to implant the multi-component device. (Tr. 80-81). In addition, as between it and the dry pack Flexi-Flate, Hydroflex came to the operating room prefilled and sterile. This was a convenience for the surgeon, but more importantly provided an added margin of safety for the patient, since prefilling with extra clean saline made the valves less prone to jamming, so the implant was less likely to require removal. The other impotence treatments had their own individual spectrum of properties, benefits and constraints that clearly differentiated one from another making them unacceptable as noninfringing substitutes for the Hydroflex. (Tr. 80-82, 690-92, 726-32). Drug therapy was nonsurgical but was prone to causing priapism, involved sticking needles into the penis, which caused scar tissue to develop. (Tr. 60-61). The rods were inexpensive and had low incidence of malfunction, but were hard to conceal and provided only adequate rigidity for coitus. The multi-component inflatables provided the best concealment and flaccidity but involved more invasive surgery and had leakage and malfunction problems similar to the dry pack Flexi-Flate. Further, the realities of the market are not such that other impotence treatments would have captured a significant amount of the sales made by the infringing wet pack Flexi-Flate, despite a difference in the products. In this regard, the court found the testimony of Drs. Bruskewitz and Latham most convincing. Dr. Brus-kewitz, an implanting urologist and a highly credible witness, explained how he and other implanters typically explained the options available to patients: [W]hen it comes to the treatment itself, we have a discussion with the patients about all the various options in some detail. It’s often a léngthy discussion, sometimes two discussions in which we spell out the treatment options; psychological therapy, drug injections, vacuum devices, penile implants. And we try and be as detailed as reasonably possible so that the patient is a part of the decision. (Tr. 63). If the doctor and patient agreed that an implant appeared to be the treátment best suited to the patient, a number of factors specific to devices were discussed, including reliability, concealability, cost, ease of insertion, manual dexterity necessary to operate, and degree of rigidity. (Tr. 90-91). Sometimes after the discussion the patient elected no treatment. (Tr. 77). More often, the patient and doctor would decide upon a device after weighing the advantages and disadvantages of the various implants. The court finds that those who chose the Hydroflex or the infringing wet pack Flexi-Flate did so after careful deliberation; recognizing the unique set of advantages and disadvantages presented by that particular type of device. They were attracted to it by its good flaccidity and rigidity (better than the rods but not as good as the multicomponent), less invasive surgery (a factor with the multicomponent), and the fact that prefilling made the device less prone to malfunction (a factor with the multi-component and the dry pack Flexi-Flate). The patients who selected the self-contained inflatable would not have chosen a different type of device had the wet pack Flexi-Flate not been on the market. The court also found Dr. Latham’s testimony helpful on the issue of availability of noninfringing substitutes. Dr. Latham is a professor of economics specializing in quantitative microeconomics, the quantitative study of how individual firms, households and persons decide how to spend their limited resources. Dr. Latham posited that the only way to accurately measure people's preferences for the relative advantages and disadvantages of various products during a historical period, in this case 1986-87, was to examine their purchasing choices, as reflected by market data. (Tr. 845-49). Using this, method, Dr. Latham concluded that 1) self-contained inflatables are a submarket within the larger impotence products market (Tr. 822-25); and 2) the dry pack Flexi-Flate was not a serious competitor in this market once AMS was able to overcome the backorder problem with the Hydroflex. (Tr. 797-812, 824, 860-66). Dr. Latham’s testimony was very credible, and the court finds that it supports the conclusion that a noninfringing substitute for the Hydroflex did not exist. After hearing his testimony, observing his demeanor and studying his survey data, the court must to reject the conclusions of MEC’s economist, Dr. Lewis Solmon. Dr. Solmon conducted a survey of urologists in 1990 which attempted to demonstrate the “decision process underlying the choices by urologists of particular penile prosthetic devices.” (Ex. 1015 at 2). The survey, however, is seriously flawed in many respects and as a consequence fails to convince the court of the availability of acceptable substitutes in the penile implant market in 1986-87. Flaws in the survey include the following. First, the court has serious doubts about whether it is possible to survey in 1990 the preferences of persons in 1986-87 with any degree of accuracy. In this regard, the court chooses to credit Dr. La-tham’s assertion that it is poor technique for an economist to utilize a survey to obtain the preferences of consumers. Second, the survey fails to address the reality that the patient and the physician choose the particular type of implant together. As was clear from the testimony of Dr. Bruskewitz and the other urologists, the patient had substantial input into which device was appropriate for his lifestyle. Third, to the extent that it would be appropriate to study urologists, Dr. Solmon did not study the appropriate population of urologists, namely actual implanters of penile protheses active in 1986-87. (Tr. 2157-62, 2173-74). Fourth, the response rate to the survey of about six percent was well below acceptable limits, and no post-survey attempts were made to determine how representative the respondents were of the total relevant population. (Tr. 2155, 2165-77, 2180-82). Fifth, the terms used and the questions asked were not pretested and were in many instances confusing, overlapping and uncertain in meaning, particularly regarding terms like “consider” and “packaging.” (Tr. 2154, 2184-97; see also 1806-08, 121). Sixth, Dr. Solmon was inexperienced in conducting surveys of this nature. (Tr. 2156). Seventh, no evidence was presented regarding the mailing, receipt, coding or accuracy of the data. (Tr. 2156). Eighth, the survey was mailed to the same population twice, with no care taken to avoid multiple responses from the same doctor. (Tr. 2182-83). Finally, the court turns to the question of whether AMS has proved the amount of profit it would have made on each of the Hydroflex units it would have sold but for the sale of the infringing Flexi-Flate. The court concludes, based on the lengthy testimony of Dr. Latham, the deposition testimony of AMS controller Robin Cleveland, and documents prepared by AMS, that AMS would have obtained incremental income of $2,072 for every additional unit of Hydroflex that it would have sold in the United States, and $888 for every international sale during the period July 1,1986 to December 31, 1986. The court further finds that during 1987, the AMS would have enjoyed an incremental income of $2,266 for every additional Hydroflex it sold in the United States and $832 for every international sale. (Ex. 100, 112; Tr. 812, 817-21, 836, 918-99). MEC has presented no evidence to suggest that AMS’ incremental profit calculations are incorrect. Thus, the lost profits to which AMS is entitled may be calculated by multiplying the per unit incremental profit times the number of infringing sales made during the relevant time period. B. Patent Marking MEC claims AMS may only recover limited damages for two reasons. First, MEC claims AMS failed to mark the Hydroflex with the word “patented” until long after the patent issued. In addition, MEC claims that AMS never provided “notice” of the claimed infringement until this lawsuit was filed on October 28, 1987. As a result, MEC claims it is only liable for damages from the date of filing. The Patent Act imposes on patent owners a duty to mark patented articles. 5 D. Chisum, Patents, sec. 20.03[7][c] at p. 20-249. However, where a patent claims only a method (as opposed to a product, or a method and a product) there is no duty to mark. Bandag, Inc. v. Gerrard Tire Co., Inc., 704 F.2d 1578, 1581 (Fed.Cir.1983) citing Wine Railway Appliance Co. v. Enterprise Railway Equipment Co., 297 U.S. 387, 56 S.Ct. 528, 80 L.Ed. 736 (1936). This is not surprising since one cannot mark an abstraction. A somewhat more problematic question is whether there is a duty to mark when the patent contains both product and method claims. In Devices for Medicine v. Boehl, 822 F.2d 1062 (Fed.Cir.1987), the court indicates that where there are both product and method claims being claimed infringed, the patentee must mark the product. This is consistent with the spirit of the patent marking statute, requiring the patentee to put the world on notice of his patent if he is to collect damages. It makes good sense to require patentees to mark their products even if the patent also alleges