The opinion of the court was delivered by: Vaughn R Walker United States District Chief Judge
Following the dismissal of various claims, this suit now focuses on United Stats Patent No 5,333,273, which discloses a "protected hot key function for microprocessor-based computer system." The invention is in the field of computer circuitry and, more particularly, keyboard-input processing for ISA-compatible personal computers. The court held a claim construction hearing on May 6, 2005, pursuant to Markman v Westview Instruments, Inc, 517 US 370 (1996). Based on the hearing, the parties' memoranda and the applicable Federal Circuit law, the court construes the claims of the patent as follows.
The patent in suit has been the subject of considerable litigation, both in this court and in the Southern District of Texas before Magistrate Judge Johnson and Judge Rainey. Between the patent itself, the parties' memoranda, Judge Johnson's report and recommendation (the "Texas R&R," reproduced at Joint Statement (Doc #196) Ex 1) and Judge Rainey's claim construction order (the "Texas Order," also reproduced at Joint Statement (Doc #196) Ex 1), the invention has been exhaustively described. Accordingly, the barest outline will suffice here.
As the patent explains, activity on ISA-compatible computers typically proceeds via an "interrupt," which causes the computer's CPU to stop one activity and start another. Various interrupts (conventionally labeled in ISA-compatible computers as IRQ0, IRQ1, IRQ2 and so on) are associated with various functions. Conventionally, the "IRQ1" interrupt is associated with keyboard input; when the CPU receives an IRQ1 interrupt, it stops its activity to receive a "scan code" from the keyboard. This scan code signifies that a certain key has been depressed or released, and the CPU will then execute software instructions in response to the particular scan code. Such software instructions are specific to the software that a user has loaded onto the computer. For example, pressing the "A" key on the keyboard while running a word processing program will, typically, cause the letter "a" to appear in the active document. More exotically, particular keys or key combinations that call up a program or perform a certain function are often known as "hot keys." If two loaded programs are both designed to respond to the same hot key, the resulting conflict can cause the computer not to function in the way the user expects.
The patent is directed to a "protected hot key function" whose behavior is not as readily altered or customized by user-loaded software as conventional hot keys. The invention describes an "additional function key," which, when depressed on its own or in combination with a conventional key or keys, causes a second interrupt -- i e, an interrupt other than the IRQ1 interrupt conventionally used in ISA-compatible computers. Apparently, at the time of the invention, little if any software existed that would respond to this second interrupt, thus ensuring that computer manufacturers could reliably assign predictable behaviors to hot keys using the additional function key (or to the additional function key on its own) without interference from user-loaded software.
The construction of patent claims is a question of law to be determined by the court. Markman v Westview Instruments, Inc, 517 US 370 (1996). The goal of claim construction is "to interpret what the patentee meant by a particular term or phrase in a claim." Renishaw PLC v Marposs SpA, 158 F3d 1243, 1249 (Fed Cir 1998). In determining what a patentee meant by a term or phrase, the court looks first to the claim itself.
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 USC § 112. It is to these wordings that one must look to determine whether there has been infringement. Courts can neither broaden nor narrow the claims to give the patentee something different than what he has set forth. No matter how great the temptations of fairness or policy making, courts do not rework claims. They only interpret them.
EI Du Pont de Nemours & Co v Phillips Petroleum Co, 849 F2d 1430, 1433 (Fed Cir 1988).
"The claims define the scope of the right to exclude; the claim construction inquiry, therefore, begins and ends in all cases with the actual words of the claim." Renishaw, 158 F3d at 1248. "The words used in the claim are viewed through the viewing glass of a person skilled in the art." Brookhill-Wilk 1, LLC v Intuitive Surgical, Inc, 326 F3d 1215, 1220 (Fed Cir 2003) (citing Tegal Corp v Tokyo Electron Am, Inc, 257 F3d 1331, 1342 (Fed Cir 2001)). "Absent a special and particular definition created by the patent applicant, terms in a claim are to be given their ordinary and accustomed meaning." York Prods, Inc v Central Tractor Farm & Family Ctr, 99 F3d 1568, 1572 (Fed Cir 1996). The court may, if necessary, consult a variety of sources to determine the ordinary and customary meaning of a claim term, including the claim terms themselves, dictionaries, the written description, the drawings and the prosecution history, if in evidence. Brookhill-Wilk 1, 326 F3d at 1220. "Such intrinsic evidence is the most significant source of legally operative meaning of disputed claim language." Vitronics Corp v Conceptronic, Inc, 90 F3d 1576, 1582 (Fed Cir 1996). With respect to dictionary definitions, "[i]f more than one dictionary definition is consistent with the use of the words in the intrinsic record, the claim terms may be construed to encompass all such consistent meanings." Texas Digital Systems, Inc v Telegenix, Inc, 308 F3d 1193, 1203 (Fed Cir 2002).
The court begins its construction of claim terms by consulting intrinsic evidence of the meaning of disputed claim terms, which includes the claims, the specification and the prosecution history (if in evidence). Lacks Industries, Inc v McKechnie Vehicle Components USA, Inc, 322 F3d 1335, 1341 (Fed Cir 2003) (citation omitted). "If upon examination of this intrinsic evidence the meaning of the claim language is sufficiently clear, resort to 'extrinsic' evidence, such as treatises and technical references, as well as expert testimony when appropriate, should not be necessary." Digital Biometrics, Inc, v Identix, Inc, 149 F3d 1335, 1344 (Fed Cir 1998). "[I]f after consideration of the intrinsic evidence, there remains doubt as to the exact meaning of the claim terms, consideration of extrinsic evidence may be necessary to determine the proper construction." Id.
"[A] court may constrict the ordinary meaning of a claim term in * * * one of four ways[:]" (1) "if the patentee acted as his own lexicographer and clearly set forth a definition of the disputed claim in either the specification or prosecution history;" (2) if the intrinsic evidence shows that the patentee distinguished the term from prior art on the basis of a particular embodiment, expressly disclaimed subject matter, or described a particular embodiment as important to the invention; (3) "if the term chosen by the patentee so deprives the claim of clarity as to require resort to other intrinsic evidence for a definite meaning; and (4) "if the patentee phrased the claim in step-or means-plus-function format," then "a claim term will cover nothing more than the corresponding structure or step disclosed in the specification, as well as equivalents thereto * * *." CCS Fitness, Inc v Brunswick Corp, 288 F3d 1359, 1366-67 (Fed Cir 2002) (internal citations and quotation marks omitted).
Limitations from the specification, such as from the preferred embodiment, cannot be read into the claims absent an express intention to do so. Teleflex, Inc v Ficosa North Am Corp, 299 F3d 1313, 1326 (Fed Cir 2002) ("The claims must be read in view of the specification, but limitations from the specification are not to be read into the claims."). But "a construction that excludes a preferred embodiment 'is rarely, if ever, correct.'"
C R Bard, Inc v United States Surgical Corp, 388 F3d 858, 865 (Fed Cir 2004) (citing Vitronics, 90 F3d at 1583).
With these legal principles in mind, the court now turns to the construction of the disputed claim language of the patent.
Independent claims 1 and 5 and several dependent claims are at issue. For many terms, the parties have stipulated to constructions (either of their own accord or by adopting the Texas construction). The court accepts those stipulations for purposes of this action. The claims -- with disputed language underscored the first time it appears -- are rescribed below. (The dependent claims about which there are no disputes are not rescribed.)
1. A system for providing a built-in function in an ISA-compatible computer in response to activation of a selected combination of user activated keys, comprising: a keyboard having a set of conventional alphanumeric and function keys and further having at least one additional function key; a keyboard controller connected to said keyboard to monitor said conventional keys and said additional function key to detect when at least one of said keys is activated, said keyboard controller having first and second interrupt signal lines connected to said ISA-compatible computer, said keyboard controller responsive to an activation of at least one of said conventional keys to activate a first interrupt signal to said ISA-compatible computer on said first interrupt signal line, said keyboard controller responsive to an activation of said additional function key in combination with at least one of said conventional alphanumeric keys to generate a second interrupt signal to said ISA-compatible computer on said second interrupt signal line; a first conventional interrupt handling routine within said ISA-compatible computer responsive to said first interrupt signal from said keyboard controller to input data scan codes from said keyboard; and a second non-conventional interrupt handling routine within said ISA-compatible computer responsive to said second interrupt signal from said keyboard controller to input an identification of said activated alphanumeric key and to perform a predetermined function selected by said identified alphanumeric key.
4. The system for providing a built-in function as defined in claim 1, further comprising a central processing unit that indexes a first memory location pointer in response to said first interrupt signal, said central processing unit further indexing a second memory location pointer in response to said second interrupt signal
5. A system for servicing keyboard interrupts in an ISA-compatible computer, comprising: a keyboard having a plurality of keys including conventional alphanumeric keys, conventional symbol keys, conventional function keys and conventional cursor control keys, said keyboard further including at least one non-conventional function key, said keyboard generating a scan code in response to an activation of at least one of said keys, said scan code varying depending upon which of said keys is activated; and a keyboard controller coupled to said keyboard, said keyboard controller further coupled to said ISA-compatible computer by first and second interrupt signal lines, said keyboard controller generating a first interrupt signal on said first interrupt signal line upon receipt of a scan code corresponding to one of said conventional keys, said ISA-compatible computer programmed to execute a program to input said scan code in response to said first interrupt signal, said keyboard controller generating a second interrupt signal on said second interrupt signal line upon receipt of a scan code corresponding to said non-conventional function key, said ISA-compatible computer programmed to execute at least one special routine upon receipt of said second interrupt signal.
Thus, the terms to be construed are:
* "ISA-compatible computer" (claims 1 and 5)
* "additional function key" (claim 1) and "non-conventional function key" (claim 5), which the parties agree should be given the same construction
* "keyboard controller" (claims 1 and 5)
* "connected to" (claim 1)
* "second interrupt signal" (claims 1 and 5)
* "data scan code" (claim 1) and "scan code" (claim 5), which the parties agree should be ...