The opinion of the court was delivered by: Charles P. Kocoras, Chief District Judge
This matter comes before the court on the parties' requests for a construction of disputed terms within the claims of two patents. The terms at issue are construed as set forth below.
Plaintiffs IP Innovation and Technology Licensing Corporation (collectively referred to as "IP") own United States Patent No. 5,424,780 ("the '780 patent") and United States Patent No. 6,529,637 ("the '637 patent"). The original inventor of the two patented inventions is Carl Cooper. In the two complaints initiating these companion cases, IP alleges that Defendants Lexmark International, Inc. ("Lexmark") and Dell Corporation ("Dell") manufacture, sell, or offer to sell printers or fax machines that infringe one or both of the patents. In conjunction with its answer to IP's complaint, Dell filed a counterclaim seeking a declaratory judgment of invalidity of the patents as well as non-infringement. Although the pleadings do not specify any product other than printers or fax machines, the briefs indicate that Dell also produces televisions or other video displays that could be implicated by these proceedings.
The '780 patent describes an apparatus and method for improving the apparent visual quality of an image. The invention addresses an artifact that occurs when display devices show diagonal lines in low-resolution images as a series of diagonal blocks resembling a set of stairs rather than as a smooth and uniform line. The invention enables the device displaying the image to use information already within the image to change the illumination of image elements, making the image appear more refined without actually increasing its resolution or size. The original patent, issued in June 1995, contains 41 claims; a reexamination certificate issued in July 2002 amended certain aspects of the prior patent and increased the number of claims to 149.
The '637 patent, which contains 215 claims, was filed on March 3, 1993, as a continuation-in-part of the '780 patent. Rather than focusing on the invention contained in the '780 patent, the '637 patent is directed to a circuit used within the invention.
Patent claims are construed as a matter of law. See Markman v. Westview Instruments, Inc., 517 U.S. 370, 372, 116 S.Ct. 1384, 1387 (1996). In general, claim terms are given the meaning they would have to a person of ordinary skill in the art at the time of the effective filing date of the application for the patent involved. See Phillips v. AWH Corp., 415 F.3d 1303, 1312-13 (Fed. Cir. 2005) (en banc).*fn1 To determine what a person of ordinary skill would understand the term to mean at the operative time, a court first considers the language of the claims themselves, the patent's specification, and the history of the patent's prosecution before the Patent and Trademark Office ("PTO") -- the intrinsic evidence. See Unique Concepts v. Brown, 939 F.2d 1558, 1561 (Fed. Cir. 1991). The intrinsic evidence forms the public record of what the patentee claimed, and the public is entitled to rely upon this record first and foremost to delineate the patent's scope. Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1583 (Fed. Cir. 1996).
In construing a particular claim term, a court must look first to the language of the claim or claims in which the term appears. Phillips, 415 F.3d at 1314. It provides a significant amount of information of the meaning of particular terms through context and relationship to other claims, whether asserted or unasserted. Id. Because the use of particular terms is usually consistent, use of a term in one claim of the patent can provide insight into its meaning when it is used elsewhere as well. Id. The language of the claims is further illuminated by the specification; it is both highly relevant to and often dispositive of the meaning of a disputed term. Id. at 1315. However, the specification is not without pitfalls; limitations found within it cannot be read into claims that do not contain the same limitations. See Golight, 355 F.3d at 1331. The final piece of the intrinsic evidence of a term's meaning is the prosecution history. It may shed light on the definition of a disputed term and must be consulted to determine whether the patentee gave a special meaning to a term or disclaimed certain aspects of the invention in the course of obtaining PTO approval. See generally id. at 1331-33.
All other indications of a patent term's meaning derive from so-called extrinsic evidence, such as dictionaries, learned treatises, and expert and inventor testimony. Because extrinsic evidence is not necessarily available to the public as part of the patent record, it should only be relied upon in situations where the terms of a patent are still ambiguous after an examination of the intrinsic evidence. Phillips, 415 F.3d at 1317-19. Whatever extrinsic sources are consulted, they must not be allowed to contradict claim language that is unambiguously set forth in the intrinsic evidence. Id. at 1324.
With these principles in mind, we begin our examination of the disputed terms.
The parties dispute the meanings of certain terms within claims 15, 109, 110, and 146 of the '780 patent. Because they seek construction of a fairly large number of terms, we will proceed with the analysis claim by claim. Several disputed terms appear in multiple claims and some in both patents; unless specified otherwise, the construction given for the first appearance of the term will apply to all other appearances of the same term. See Rexnord Corp. v. Laitram Corp., 274 F.3d 1336, 1342 (Fed. Cir. 2001).
Claim 15 is an independent claim, meaning that it does not refer back to or limit another claim in the patent. See 37 C.F.R. § 1.75. As such, it is broader than any claims dependent upon it. See Innova/Pure Water, Inc. v. Safari Water Filtration Sys., Inc., 381 F.3d 1111, 1123 (Fed. Cir. 2004). The text of the claim reads:
A method of improving the quality of an image which may be displayed on an image display device, the image made up of a number of image elements, including the step of selecting a plurality of pixels of said image, the step of comparing a first of said selected pixels to at least a second of said selected pixels to select voids of said image to be altered and including the further step of altering voids in said image in response to said comparing step thereby improving the apparent resolution of the image without requiring an increase in the number of image elements originally making up the image.
The parties' first dispute focuses on whether the preamble of claim 15*fn2 should be construed as a limitation on the claim itself. To determine the amount of import that should be ascribed to the preamble, we must examine the claim as a whole. See Pitney Bowes, Inc. v. Hewlett-Packard Co., 182 F.3d 1298, 1305 (Fed. Cir. 1999). If the claim's overall meaning depends on the preamble, it should be read as part and parcel of the rest of the claim. See id. For instance, when terms used in the preamble serve as the antecedent of limitations within the claim body, those terms are a necessary part of the claim as a whole. See Eaton Corp. v. Rockwell Int'l Corp., 323 F.3d 1332, 1339 (Fed. Cir. 2003). If the preamble gives information such as the invention's purpose or intended use that does not impact or clarify the claim's meaning, it will not limit the terms within the main claim. See Pitney Bowes, 182 F.3d at 1305. In addition, when an inventor clearly relies on the preamble to separate the claimed invention from the prior art, it is proper to construe the preamble as a claim limitation, since it serves to define the claimed invention, at least in part. Catalina Mktg. Int'l, Inc. v. Coolsavings.com, Inc., 289 F.3d 801, 808 (Fed. Cir. 2002).
The preamble of claim 15 introduces three key terms: "image," "image display device," and "image elements." The first appears within the body of the claim four times; the third is used once. Also, the prosecution history reveals that Cooper added the phrase "the image made up of a number of image elements" during prosecution to highlight the distinctiveness of his invention over the prior art. S/N 08/119,710 O.A. response 3/7/94 at 2, 12-13.
The second term, "image display device," does not appear in the body of claim 15, but it is contained in claim 109, a claim that refers back to claim 15 and thus is dependent upon it. See 37 C.F.R. § 1.75. Without the antecedent use of the term in claim 15, the reference in claim 109 would make no sense. Furthermore, the use of the term "image display device" is integral to the overall meaning of claim 15 because without it, the scope of devices that could use the invention would be unlimited. See Pitney Bowes, 182 F.3d at 1305.
Because terms within the preamble both provide an antecedent basis for terms within the main body of the main claim and a dependent claim and allowed Cooper to distinguish his invention from the prior art during prosecution, we conclude that they must be read as a limitation on the claim itself.
b. "Image Display Device"
The next disputed term in claim 15 is "image display device."*fn3 IP argues that this term includes printers, whereas Lexmark and Dell contend that it encompasses only devices that display a video image on a screen. Both sides look to the prosecution history of the '780 patent to support their respective positions.
During prosecution, Cooper sought to add a description of printers to the original specification, new claims that included printers, and a new figure. The original examiner more than once rejected the amendments as new matter. Cooper eventually petitioned the Commissioner for Patents to overrule the rejections, but the petition was dismissed because his request should have been directed to the Board of Patent Appeals and Interferences.
Cooper cancelled the relevant claims and figure and petitioned the Commissioner again. However, he did not remove all references to printers in the specification. This time, the Commissioner found the petition was moot because the "new subject matters ha[d] either been deleted or cancelled by the petitioner." See S/N 07/355,461 Commissioner's Decision 1/24/94 at 1. Before the Commissioner issued this decision, Cooper filed a continuation application, which was assigned to a new examiner, who never officially withdrew the previous new matter rejections. Some of the terms the prior examiner found objectionable appear in the patent as issued. Lexmark and Dell argue that the rejections relating to printer terminology in the patent should exclude printers because the new matter rejections were never officially withdrawn. Although the prosecution history is less than pristine in this case, we disagree with Lexmark and Dell on its overall effect on this issue for several reasons.
First and foremost, Lexmark and Dell's argument would require us to ignore the references to printers within the specification, in essence writing them out of the patent entirely, which is not a proper exercise in circumstances such as these. See Purdue Pharma L.P. v. Boehringer Ingelheim GMBH, 237 F.3d 1359, 1364 (Fed. Cir. 2001) (refusing to limit claims to single-dose administrations of medication when specification made reference to both single and multiple doses).
Second, the language of dependent claim 109 indicates that video monitors are but one kind of display device.*fn4 The doctrine of claim differentiation creates a presumption that each claim in a patent differs in scope from any other claim. See Comark Communications, Inc. v. Harris Corp., 156 F.3d 1182, 1187 (Fed. Cir. 1998). When applied in the context of dependent and independent claims, the doctrine generally leads to a conclusion that dependent claims are narrower than the claim on which they depend. Phillips, 415 F.3d at 1315. The presumption is extremely strong when the only meaningful difference between the independent and dependent claims is the limitation at issue, and one party is requesting that the limitation present in the dependent claim be imported into the independent claim. See Sunrace Roots Enterprise Co., Ltd. v. SRAM Corp., 336 F.3d 1298, 1303 (Fed. Cir. 2003). To construe the claims in another fashion would typically render the dependent claims superfluous, a result we must strive to avoid. See Comark, 156 F.3d at 1187. Here, the limitation that Lexmark and Dell contend to be omnipresent in the term "image display device" is the very limitation made explicit in claim 109. Thus, the presumption that "image display device" applies to devices other than video monitors weighs particularly heavily in favor of IP's construction.
Third, Lexmark and Dell's primary support for their argument comes from a definition of "display"*fn5 that states, in pertinent part:
1. A visible representation of information in words, numbers or drawings, as on the cathode-ray tube screen of a radar set, navigation system, or computer console.
2. The device on which the information is projected. Also known as display device.
McGraw-Hill Dictionary of Scientific and Technical Terms, 593 (5th ed. 1994). Lexmark and Dell emphasize that the phrase "as on the cathode-ray tube screen" is especially supportive to their position, arguing that the inclusion of this phrase necessarily excludes other examples of display devices. Extrinsic evidence can be helpful in understanding the state of the art when a patent application was filed, but it cannot be used to contradict the plain language of the patent as issued. See Phillips, 415 F.3d at 1324. The construction that Lexmark and Dell propose would do more than explain the intrinsic evidence; it would stand in direct conflict.
Moreover, extrinsic evidence must be considered in the context of the intrinsic evidence. See id. at 1319. When so viewed, the definition upon which Lexmark & Dell rely actually supports the conclusion that printers can be considered a "display device." The most natural reading of the definition reveals that the examples given are illustrative, not exhaustive. Printers, particularly laser printers, are capable of projecting a visible representation of information onto paper. Accordingly, we cannot agree with Lexmark and Dell that this definition excludes printers from its scope.
Lastly, in support of their argument, Lexmark and Dell rely on Dresser Indus., Inc. v. United States, 432 F.2d 787 (Ct. Cl. 1970), in which the patentee filed a § 312 amendment that redefined certain terms in a way that was inconsistent with the original specification. In that case, the court did not use the new language because it was clear that the amended text constituted new matter. Id. at 794. Here, by contrast, the history does not unequivocally indicate that a person of ordinary skill in the art would not have understood that the invention applied to printers.
Therefore, the court defines "image display device" as follows: a device for providing an image that may be viewed by a viewer. This construction will apply equally to the use of this term in claim 109 of the '780 patent.
c. "Pixel" and "Image Element"
The next two terms we must consider, "pixel" and "image element," are undeniably related, but the issue we need to decide is the extent of their similarity. IP differentiates between these two concepts; Lexmark and Dell ask that they be considered synonymous.*fn6 According to IP, "pixel" refers to the smallest complete element of an image, and it can be formed of subpixels that contribute to the formation of a complete element but that are not complete in themselves. IP urges a broader construction for "image element" as any element found within an image, including complete pixels, portions of pixels, and other elements of images that are not pixel-related.*fn7 Lexmark and Dell insist that "pixel" and "image element" are interchangeable. In their opinion, both terms refer to the smallest electronically coded part of an electronically coded input image. When the terms are used in the context of discussing a display device, Lexmark and Dell argue that they must mean the smallest addressable element of the display device.
An examination of the intrinsic evidence reveals that IP has the better argument. For example, the specification of the '780 patent states that "[v]oids in the image may be filled with all or a portion of a pixel," which is consistent with IP's position that pixels can be formed of subpixels. U.S. Patent No. 5,424,780, col. 4, lns. 50-51; see also col. 5, lns. 48-50 ("New pixels or pixels used for filling, substitution or replacement may be comprised of all or a portion of a pixel."). Examples could include the RGB components of a video signal or the yellow, cyan, and magenta components of a single pixel used in laser printing.
Although in many circumstances the patents use the terms interchangeably, that is not inconsistent with IP's proposed definitions, wherein all pixels are image elements, but not all image elements are pixels. Though the intrinsic evidence from the '780 patent does not provide a great deal of illumination on these issues, the language of the '637 patent directly supports IP's position. The parties agree, and we concur, that the terms "image element" and "pixel" should be construed consistently as to both patents, so the guidance provided by the '637 patent clarifies the meaning of these terms in the '780 patent as well. Dependent claims 34, 51, 140, and 161 all have one limitation that states: "image elements are pixels." Here again, the doctrine of claim differentiation provides helpful guidance. See Comark, 156 F.3d at 1187. When applied to these four claims, the doctrine supports the conclusion that the image elements referenced in the independent claim are not always pixels, which indicates that they should not be treated as synonyms.
Furthermore, though the intrinsic evidence gives no indication that Cooper intended these terms to carry an idiosyncratic meaning, Lexmark and Dell's proposed definition adds in requirements that pixels and image elements must be an addressable element contained in electronically coded input image. They have not provided convincing support that these aspects are included in the ordinary and customary meaning of these terms, nor ...