Rehearing Denied; Suggestion for Rehearing In Banc Declined November 18, 1998.
This appeal requires us to determine whether the district court made errors of claim construction that resulted in an erroneous finding of noninfringement at the close of a bench trial. See Renishaw PIC v. Marposs Societa' Per Azioni, 974 F.Supp. 1056 (E.D.Mich.1997). At trial, Renishaw plc (Renishaw) asserted that four claims from three patents were infringed by the Mida product line of touch probes produced by Marposs Societa' per Azioni and Marposs Corporation (collectively Marposs). Renishaw appeals only the finding of noninfringement of claim 2 of its U.S. Patent No. 5,491,904 (the '904 patent). Because we conclude that the district court properly found one limitation of the claim not satisfied, we affirm.
The '904 patent, listing David McMurtry as its inventor, describes and claims an improved touch probe. Touch probes are used in the automated manufacturing and measurement field to check with extreme precision the dimensions of machined parts. A touch probe consists of a long, thin stylus that extends out from a housing and that can deflect in all directions. The probe, which is mounted on a movable arm of a machine, produces an electrical "trigger" signal when the stylus contacts a workpiece to be measured. A computer that controls the movement of the arm uses the trigger signal to calculate the dimensions or location of the workpiece. Although the stylus can be several inches long, a touch probe often exhibits accuracy on the order of one micron (one millionth of a meter) or less. This relatively small dimension must be kept in mind when discussing the attributes of touch probes. Figures 1 and 2 of the '904 patent show one embodiment of the patented touch probe in vertical and horizontal cross-section, respectively:
In these figures, an inverted cup, or stylus holder
The embodiment just described purportedly solves two problems in the prior art: lobing and hysteresis. Lobing occurs when, because of the way the stylus holder is mounted in the housing, a greater amount of stylus deflection is required to trigger the probe in some directions than in others. The pictured embodiment reduces lobing because the annular skirt results in equal deflection in every direction. Because the probe triggers upon relatively equal deflection in any direction, it can achieve micron-level accuracy by signaling soon after the stylus contacts a workpiece.
Hysteresis occurs when the stylus returns to a different position after each deflection (i.e., the stylus does not center fully); it is caused primarily by friction between the probe components. The pictured embodiment reduces hysteresis because the biasing spring pushes the cylinders tightly into their seats between the balls, returning the stylus to the same rest position each time. The key issue on appeal is whether the claimed touch probe solves both these problems. Claim 2 recites (emphasis added):
In the Mida probes, the stylus holder ("armset" in the diagram) has a spherical surface that rests in a conical seat in the housing and a central extension that rises toward a microswitch. The stylus holder also has an annular member ("disk" in the diagram), but unlike the annular skirt in the preferred embodiment of the '904 patent, it does not normally rest flat against the housing. Rather, it rests above a shelf built into the side of the housing and is separated from the shelf by a small gap. Thus, when the stylus contacts an object, the stylus holder does not immediately move upward toward the microswitch. Instead, it first rotates inside the conical seat (like a ball-and-socket joint). Once the annular disk hits the shelf, the stylus holder tips upward and its central extension hits the microswitch.
The annular ring cannot rest in flat contact with the shelf, and therefore, the spring can only force the stylus to return to a "neutral zone" rather than to a single precise rest position. As a result, the Mida probes are not designed to signal as soon as the stylus begins to move. Instead, they do not signal until the probe reaches the edge of the neutral zone. Because the size of the neutral zone is known, the location of the object being measured can be calculated. Thus, although the Mida probes do not eliminate hysteresis, they nonetheless provide precise readings.
Renishaw sued Marposs in July 1994, and a bench trial on infringement was held in March 1997. During the trial, Marposs presented no evidence regarding invalidity. At the close of the evidence, the district court took the case under advisement and requested proposed findings and post-trial briefs from both sides. In August 1997, the court found that none of Marposs's accused touch trigger probes infringed any of the asserted patent claims. Renishaw appeals the finding of noninfringement only with respect to claim 2 of the '904 patent. We have jurisdiction under 28 U.S.C. § 1295(a)(1) (1994).
An infringement analysis is a two-step process in which we first determine the correct claim scope, and then compare the properly construed claim to the accused device to determine whether all of the claim
On appeal, Renishaw asserts that the district court erred in construing three separate limitations in claim 2 and that those errors resulted in the court's erroneous finding of noninfringement. We address the claim requirement that the "probe generat[e] a trigger signal when said sensing tip contacts an object." Renishaw contends that the district court improperly read a limitation into this claim limitation from the '904 patent's written description.
Renishaw, of course, alludes to a familiar pair of claim construction canons: (a) one may not read a limitation into a claim from the written description, but (b) one may look to the written description to define a term already in a claim limitation, for a claim must be read in view of the specification of which it is a part. These two rules lay out the general relationship between the claims and the written description. See Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582, 39 USPQ2d 1573, 1576 (Fed.Cir.1996); Markman v. Westview Instruments, Inc., 52 F.3d 967, 979-80, 34 USPQ2d 1321, 1329-30 (Fed. Cir.1995) (in banc), aff'd, 517 U.S. 370, 116 S.Ct. 1384, 134 L.Ed.2d 577, 38 USPQ2d 1461 (1996). As rules at the core of claim construction methodology, they provide guideposts for a spectrum of claim construction problems.
Although no canon of construction is absolute in its application,
Thus, a party wishing to use statements in the written description to confine or otherwise affect a patent's scope must, at the very least, point to a term or terms in the claim with which to draw in those statements. Without any claim term that is susceptible of clarification by the written description, there is no legitimate way to narrow the property right. The Supreme Court has clearly stated the rationale for this requirement:
McCarty v. Lehigh Val R.R., 160 U.S. 110, 116, 16 S.Ct. 240, 40 L.Ed. 358 (1895). If we need not rely on a limitation to interpret what the patentee meant by a particular term or phrase in a claim, that limitation is "extraneous" and cannot constrain the claim. See Hoganas AB v. Dresser Indus., Inc., 9 F.3d 948, 950, 28 USPQ2d 1936, 1938 (Fed. Cir.1993) ("It is improper for a court to add `extraneous' limitations to a claim, that is, limitations added wholly apart from any need to interpret what the patentee meant by particular words or phrases in the claim.") (quoting E.I. du Pont de Nemours & Co. v. Phillips Petroleum Co., 849 F.2d 1430, 1433, 7 USPQ2d 1129, 1131 (Fed.Cir.1988)); see also Specialty Composites v. Cabot Corp., 845 F.2d 981, 987, 6 USPQ2d 1601, 1605 (Fed. Cir.1988) ("Where a specification does not require a limitation, that limitation should not be read from the specification into the claims.") (citing Lemelson v. United States, 752 F.2d 1538, 1551-52, 224 USPQ 526, 534 (Fed.Cir.1985)); cf. Constant v. Advanced Micro-Devices, Inc., 848 F.2d 1560, 1571, 7 USPQ2d 1057, 1065 (Fed.Cir.1988) (holding that the written description provided "no evidence to indicate that  limitations must be imported into the claims to give meaning to disputed terms").
The other clear point provided by these two canons covers the situation in which a patent applicant has elected to be a lexicographer by providing an explicit definition in the specification for a claim term. In such a case, the definition selected by the patent applicant controls. The patentee's lexicography must, of course, appear "with reasonable clarity, deliberateness, and precision" before it can affect the claim. In re Paulsen, 30 F.3d 1475, 1480, 31 USPQ2d 1671, 1674 (Fed.Cir.1994); see Intellicall, Inc. v. Phonometrics, Inc., 952 F.2d 1384, 1388, 21 USPQ2d 1383, 1386 (Fed.Cir.1992). If the patentee provides such a clear definition, the two canons require reference to the written description, because only there is the claim term defined as it is used by the patentee.
Absent a special and particular definition created by the patent applicant, terms in a claim are to be given their ordinary and accustomed meaning. See York Prods., Inc. v. Central Tractor Farm & Family Ctr., 99 F.3d 1568, 1572, 40 USPQ2d 1619, 1622 (Fed.Cir.1996) ("Without an express intent to impart a novel meaning to claim terms, an inventor's claim terms take on their ordinary meaning."); Carroll Touch, Inc. v. Electro Mechanical Sys., Inc., 15 F.3d 1573, 1577, 27 USPQ2d 1836, 1840 (Fed.Cir. 1993). Thus, when a claim term is expressed in general descriptive words, we will not ordinarily limit the term to a numerical range that may appear in the written description or in other claims. See Modine Mfg., 75 F.3d at 1551, 37 USPQ2d at 1612. Nor may we, in the broader situation, add a narrowing modifier before an otherwise general term that stands unmodified in a claim. See, e.g., Bell Communications, 55 F.3d at 621-22, 34 USPQ2d at 1821 (faulting the district court for interpreting claim term "associating" to cover only explicit, and not implicit, association); Specialty Composites, 845
However, a common meaning, such as one expressed in a relevant dictionary, that flies in the face of the patent disclosure is undeserving of fealty. As one of our predecessor courts stated in Liebscher v. Boothroyd, 46 C.C.P.A. 701, 258 F.2d 948 (CCPA 1958):
Id. at 951; see Digital Biometrics, Inc. v. Identix, Inc., 149 F.3d 1335, 1346-47, 47 USPQ2d 1418, 1426 (Fed.Cir.1998); see also Intel Corp. v. United States Int'l Trade Comm'n, 946 F.2d 821, 836, 20 USPQ2d 1161, 1174 (Fed.Cir.1991) (affirming construction of "permanent" as a relative term in light of the patent disclosure); Ashland Oil, Inc. v. Delta Resins & Refractories, Inc., 776 F.2d 281, 298, 227 USPQ 657, 668 (Fed.Cir.1985) (claim limitation requiring that a process be carried out "under substantially anhydrous conditions with the removal of water above 100°C" covered only continuous removal of water, because the written description stated that failure to remove water continously would adversely affect the process). Thus, where there are several common meanings for a claim term, the patent disclosure serves to point away from the improper meanings and toward the proper meaning.
Ultimately, the interpretation to be given a term can only be determined and confirmed with a full understanding of what the inventors actually invented and intended to envelop with the claim. See Markman v. Westview Instruments, Inc., 517 U.S. 370, 389, 116 S.Ct. 1384, 134 L.Ed.2d 577, 38 USPQ2d 1461, 1470 (1996). The construction that stays true to the claim language and most naturally aligns with the patent's description of the invention will be, in the end, the correct construction. See Young Dental, 112 F.3d at 1142, 42 USPQ2d at 1593 (affirming the district court's claim construction as "a more natural reading of the claim language" than the appellant's construction); cf. Llewellyn, supra note 2, at 401 ("Plainly, to make any canon take hold in a particular instance, the construction contended for must be sold, essentially, by means other than the use of the canon: The good sense of the situation and a simple construction of the available language to achieve that sense, by tenable means, out of the statutory language."). A claim construction is persuasive, not because it follows a certain rule, but because it defines terms in the context of the whole patent.
Following these principles, we turn to the parties' arguments.
The main dispute concerns the requirement that "the probe generat[e] a trigger signal when said sensing tip contacts an object and said stylus holder is thereby deflected relative to said housing." The district court determined that "when" is defined by reference to this entire claim limitation, such that "when" means as soon as contact is made and deflection occurs. See Renishaw, 974 F.Supp. at 1089. On appeal, Renishaw argues that "when" should receive one of its broader dictionary definitions: "at or after the time that," "in the event that," or "on condition that," so that the claim would read on a device that does not generate a trigger
The ultimate issue is the manner in which "when" defines the timing of probe triggering vis-à-vis contact of a stylus with a work-piece. The issue brings into sharp focus the convergence of the two canons of claim construction discussed above. According to Renishaw, the accused probes escape infringement only if a narrowing limitation is read into "when" from the written description. Marposs counters with an argument that the claim is properly construed to require a finding of noninfringement because the correct meaning of the claim term "when" is embedded throughout the specification.
Neither party forwards a technical meaning for "when" in the applicable industry. However, there are several closely-related, but distinct, common meanings for "when," most cited by Renishaw on appeal. These include: at or during the time that; just at the moment that; at any or every time that; at, during, or after the time that.
The explicit language of claim 2 is our starting point. There, the claim states that a signal is generated "when" there is contact with a workpiece "and said stylus holder is thereby deflected." The claim ties the signal to contact and deflection, thus showing that the trigger signal cannot occur until the probe has contacted the workpiece and the stylus has deflected some amount. In other words, contact and deflection are a condition precedent to signaling. Thus, the claim itself precludes us from viewing "when" as requiring signaling at the precise moment of contact, for some deflection must occur before signaling. The district court also recognized this. See Renishaw, 974 F.Supp. at 1071; see also Mantech Envtl. Corp. v. Hudson Envtl. Servs., Inc., 152 F.3d 1368, 1373-74 (Fed.Cir.1998) (looking to other terms in a claim to construe a limitation in dispute); Phonometrics, Inc. v. Northern Telecom Inc., 133 F.3d 1459, 1465, 45 USPQ2d 1421, 1426 (Fed.Cir.1998) (same).
Mere recognition that "when" is not limited to the precise moment of contact, however, does not make the term clear, or mandate a meaning of "when" to include any time after contact as long as a measurement is derived from stylus contact. That is because "when" is not a broad and general term when standing in isolation. Instead, it has several meanings, each of which may prevail based on the context. Here, we have bounteous context. Claim 2 does not exist in rarefied air, but rather is surrounded by a patent disclosure of singular purpose. As evidenced by the several common meanings of "when," the term is imprecise as used in the '904 patent. The term is not ambiguous, however, because the written description provides overwhelming evidence to guide a proper interpretation of the term. See Vitronics, 90 F.3d at 1583, 39 USPQ2d at 1577. Replete with references that indicate that the patentee was preeminently concerned with generating a trigger signal as soon as possible after contact, the written description lends precision to the term "when." The written description shows that the patentee's invention is directed at a machine that produces
For example, in describing the invention's place within the prior art, the '904 patent notes: "When the stylus contacts a workpiece surface, a trigger signal is generated by the probe, which is used to trigger the taking of a reading of the instantaneous position of the movable spindle, quill or arm." Col. 1, ll. 36-42. Likewise, the Summary of the Invention states that the preferred embodiment of the probe "includes means for providing a signal when said stylus contacts a workpiece," col. 3, ll. 28-29, and that the movable elements are displaced "out of said rest position when said stylus contacts a workpiece," col. 3, ll. 21-22.
Statements in the "Description of Preferred Embodiments" also use the term "when" to describe a time very close to the precise instant that the stylus contacts the object to be measured and not some appreciable time thereafter:
Col. 4, l. 52 to col. 5, l. 7. This passage refers to "when" as "at this time," i.e., when the planar spring is flexing and the cylinders, or analogously, the legs of the trampoline, have not yet lifted out of their moorings. In other passages, the written description states: "The instant at which the stylus tip
Col. 8, ll. 11-13 (emphasis added to all quotations). These passages make abundantly clear that "when" in the patent means at the time of, and not some appreciable time thereafter. See Autogiro Co., 384 F.2d at 397, 155 USPQ at 702-03 ("[W]ords must be used in the same way in both the claims and the specification.").
To the extent that these passages refer to the preferred embodiment, they cannot be read into the claims without some hook. The claim term "when" is that hook. Each of the passages above show that the patentee wanted "when" to mean as soon as possible after contact. In contrast, Renishaw's proferred construction of "when," which would sweep in any time whatsoever after contact, is so broad that it would require us to ignore the abounding statements in the written description that point decidedly the other way.
Renishaw might have us save its claim by placing a functional limitation on the claim such that "when" would permit signaling at any time after contact but no longer than would permit accurate measurement of the workpiece. However, this limitation appears nowhere in the claims; rather, it comes from a concept of operability. To the extent Renishaw must refer to the written description, the patentee's extremely detailed account of
Our construction of "when" matches that of the district court. Although the district court initially construed "when" to mean "at the time that," it recognized that its choice of words could be read out of context to require immediate signaling, a physical impossibility. The district court therefore clarified its construction as follows:
Renishaw, 974 F.Supp. at 1071. Consistent with this understanding and with the understanding that the claimed probes operate at a micron-level scale, we hold that claim 2 covers probes which signal within a nonappreciable period of time after contact such that the delay in signaling is insignificant when compared to the sensitivity and accuracy of the probe.
The operation of the Marposs Mida probes is not disputed. They signal after an appreciable amount of movement of the stylus which is well after the contact with the workpiece and initial deflection. In fact, this appreciable delay is part of the design of the Mida probes and ensures that they can operate properly without centering fully. The same delay that creates unrecoverable error in the probes disclosed in the '904 patent is necessary to provide accuracy in the Mida probes. The Mida probes can still measure precisely, but they do so by taking advantage of designed-in delay. There is thus no clear error in the court's finding that the Mida probes do not literally infringe the "when" limitation.
Renishaw hints in its submissions on appeal that Marposs's probes at least infringe by equivalents. However, Renishaw's citations to the record indicate only that the issue of literal infringement was raised at trial. Thus, there is no need to remand to the district court. We therefore affirm.