Citations
- 157 F.3d 1325
Full opinion text
PLAGER, Circuit Judge.
Desper Products, Inc. and Spatializer Audio Laboratories, Inc. (collectively “Desper”) sued QSound Labs, Inc. (“QSound”), owner of U.S. Patent Nos. 5,105,462 (the ’462 patent) and 5,208,860 (the ’860 patent), in the United States District Court for the Central District of California (No. CV 94-7276). Desper sought a declaratory judgment that Desper’s “Spatializer” product does not infringe either patent and that the patents are invalid. QSound counterclaimed for patent infringement. The district court entered summary judgment for Desper, and QSound appeals. Because the district court correctly interpreted the disputed claim language and properly concluded that QSound surrendered subject matter within which Desper’s “Spa-tializer” product falls, we affirm the judgment for Desper.
BACKGROUND
This case involves two patents, the ’462 patent and the ’860 patent, both entitled “Sound Imaging Method and Apparatus.” At the trial level, the case was assigned, with the consent of the parties, to a special master. The parties filed cross-motions for summary judgment with regard to the question of infringement. After considering both parties’ submissions, and after conducting an extensive hearing during which both sides put on expert testimony, the special master recommended that judgment of non-infringement be entered in favor of Desper, with one exception in which the special master deemed the infringement of certain claims to involve a disputed question of fact precluding summary judgment.
The district court adopted all of the special master’s recommendations, except the one in which the master thought there existed a genuine dispute of material fact. The district court concluded that Desper was entitled to summary judgment of non-infringement on all the asserted claims. The district court entered final judgment of non-infringement in .Desper’s favor under Fed.R.Civ.P. 54(b). QSound now appeals that ruling.
A. The Patented Technology
Both of QSound’s patents stem from a common application and, as such, have a common written description; only the claims differ between the two. The patents describe an audio sound image location system that processes a monaural sound signal in such a way as to create an illusion that the source of the sound is located someplace in a three-dimensional space. The patented invention gives an audiophile the ability to locate individual sounds at different locations in space in order to create a “virtual symphony.”
At the heart of the patented system is a so-called “sound processor.” A block diagram of a sound image location system incorporating two such sound processors is shown in Fig. 16 in the patents and is reproduced below:
A monaural signal is provided at terminal 1502. That signal is separated into two individual “channel signals.” Each channel signal is then processed through a separate “channel.” One channel includes sound processor 1501 while the other includes sound processor 1502. Each sound processor alters the phase and amplitude of the channel signal passed through the respective channel. The output of each sound processor can be coupled to a transducer (not shown in Fig. 16), otherwise known as a speaker, to reproduce the sound. By altering the phase and amplitude of the channel signals, the patented system allegedly can create the illusion that the sound originates from a point in 3-dimensional space away from the speakers, even though the sound actually originates from the speakers.
As is well known in the art, a transfer function is the relationship between the output of a component in a system to its input. The transfer function in the preferred embodiment of the patents was empirically derived through a laborious process, which is described in detail in the patents. The patents stress the importance of the change in amplitude and phase of one of the channel signals relative to the other. As a result of this relative relationship between the signals, one of the sound processors can be significantly reduced or even eliminated by performing all of the amplitude alteration and phase shifting on one of the channel signals. As described in the patents, the transfer functions, themselves, can be changed by position control parameters that are provided to the sound processors via terminal 1505. These position control parameters give a user the added flexibility of moving the apparent point of origin of a sound, giving a similar effect as the adjustment of “balance” or “fade” controls would in a conventional stereo.
A schematic diagram of the preferred embodiment of the patented sound processor is shown in the patents at Fig. 18a, which is reproduced below:
The phase shifting and amplitude alteration is performed in filters 1610 and 1630, which are specifically designed to impart a unique and different change in each of a plurality of successive frequency bands that comprise the audio spectrum (i.e., 20-20,000 Hz). In one embodiment of the sound processor, the bands are 40 Hz in width, thus creating approximately 500 bands within the audio spectrum. It is critical both for the operation and patentability of the invention that the phase shift and amplitude change for each of the frequency bands be individually specified. The ability to separately alter the phase and amplitude of the channel signals for each frequency band is at the heart of the invention. To implement this approach, the patent describes a filter embodiment that uses a plurality of cascaded bandpass filters, with each bandpass filter designed to impart a pre-determined phase shift and amplitude change to a corresponding frequency band.
The sound processor design shown in Fig. 18a includes six potentiometers (1651-1654, 1657,1658) to give the system added flexibility. In the preferred embodiment, four of the potentiometers (1651-1654) are controlled by a single two-axis joystick so that an operator can vary the apparent position of the sound in a smooth and continuous manner. The four potentiometers operate as follows. The monaural signal is simultaneously fed to the potentiometers 1651 and 1652. The two potentiometers 1651 and 1652 work differentially, so that an increase in one produces a corresponding decrease in the other and vice versa. The output of filter 1610 is fed to a differentially controlled potentiometer, 1653, which attenuates the output of the filter. The companion to potentiometer 1658 is potentiometer 1654, which is coupled to the output of filter 1630 in order to attenuate its output. The two potentiometers, 1653 and 1654, operate in the same complimentary manner as potentiometers 1651 and 1652.
The output of potentiometer 1653 is passed through a buffer amplifier 1655 to another potentiometer 1657 and from there to reversing switch 1659, “which allows the filter signals to be fed directly or interchanged, to first inputs of summing elements 1660 and 1670.” ’462 patent, col. 13,11. 12-14. Assuming that switch 1659 is in the position shown in Fig. 18a, the output of potentiometer 1657 is fed to summing element 1670 while the output of potentiometer 1658, which acts in unison with potentiometer 1657, is fed to summing element 1660, where it is summed with the attenuated monaural signal.
From the summing elements, the channel signals proceed to their respective output terminals 1688 and 1689. The embodiment shown in Fig. 18a permits the operator to individually select different signals by changing the settings of switches 1682, 1685, and 1691, the details of which are not relevant to the present dispute.
B. The District Court Proceedings
Before the district court, QSound asserted the four independent claims of the two patents: claims 1 and 7 of the ’462 patent; and claims 1 and 5 of the ’860 patent. The special master, in a thorough opinion, interpreted a number of disputed words and phrases in the asserted claims. The district court adopted most of the special master’s findings and recommendations. While QSound challenges many of these conclusions, we need only consider a few of the disputed phrases because they are disposi-tive. Each of the independent claims is reproduced below with the disputed claim language emphasized.
1. The Claims
a. The %62 Patent:
1. A method for producing and locating an apparent origin of a selected sound from an electrical signal corresponding to the selected sound in a predetermined and localized position anywhere within the three-dimensional space containing a listener, comprising the steps of:
separating said electrical signal into respective first and second channel signals;
altering the amplitude and shifting the phase of the signal in both said first and second channel signals while maintaining said phase and amplitude differential ther-ebetween for successive discrete frequency bands across the audio spectrum and each successive phase shift being different than the preceding phase shift, relative to zero degrees, thereby producing first channel and second channel' modified signals and creating a phase differential and an amplitude differential between the two channel signals;
maintaining the first channel signal separate and apart from the second channel signal following the step of altering the amplitude and shifting the phase; and
respectively applying said first and second channel modified signals that are maintained separate and apart and that have said phase and amplitude differential therebetween to first and second transducer means located within the three-dimensional space and spaced part [sic: apart] from the listener to produce a sound apparently • originating at a predetermined location in the three-dimensional space that may be different from the location of said sound transducer means.
7. A system for conditioning a signal for producing and locating, using two transducers located in free space, an auditory sensory illusion of an apparent origin for at least one selected sound at a predetermined localized position located within the three-dimensional space containing a listener from a single electrical signal corresponding to the selected sound, comprising: first and second channel means both receiving the same single electrical signal, said first and signal [sic: second] channel means including respective first and second sound processor means each for altering the amplitude and shifting the phase angle of the respective electrical signal on a frequency dependent basis for successive discrete frequency intervals across the audio spectrum to produce a respective modified signal wherein the amplitude alteration differential and the phase angle shift differential occurring between the two channels are respective predetermined values for each said successive frequency interval of the audio spectrum, said sound processor means shifting the phase angle such that each successive phase angle shift is different and independent of a preceding phase angle shift relative to zero degrees, and said first and second channels being maintained separate and apart prior to being fed to the two transducers.
b. The ’860 Patent:
1. A method for producing and locating an apparent origin of a selected sound from an input monaural signal corresponding to the selected sound in a predetermined and localized position anywhere within the three-dimensional space containing a listener, comprising the steps of:
separating said input monaural signal into respective first and second channel signals;
providing a sound position control signal derived independently of the input monaural signal for making amplitude and phase adjustments at each of a number of discrete frequency bands over the audio spectrum and relating to a sound location determined by azimuth, height, and depth;
altering the amplitude and shifting the phase of the signal in at least one of said first and second channels in response to said sound position control signal, both altering and shifting being done on a predetermined frequency dependent basis for successive discrete frequency bands across the audio spectrum and each successive phase shift being different than the preceding phase shift relative to zero degrees, thereby producing at least a first channel or a second channel modified signal and creating a continuous phase differential and a continuous amplitude differential between the two channel signals that varies for each of said discrete frequency bands;
maintaining the first channel signal separate and apart from the second channel signal following the step of altering the amplitude and shifting the phase; and
respectively applying at least first and second channel modified signals that are maintained separate and apart and that have said phase and amplitude differential therebetween to first and second transducer means located with [sic: within] the three-dimensional space and spaced apart from the listener to produce a sound apparently originating at a predetermined location in the three dimensional space that may be different from the location of said sound transducer means.
5. A system for conditioning a signal for producing and locating, using two transducers located in free space, an auditory sensory illusion of an apparent origin for at least one selected sound at a predetermined localized position located within the three-dimensional space containing a listener from a single monaural input signal corresponding to be selected sound, comprising: first and second channel means both receiving the same single monaural input signal, one of said first and signal channel means including sound processor means connected to receive a sound position control signal derived independently of the input monaural signal for controlling amplitude and phase adjustments at each of a number of selected frequency intervals of the audio spectrum and relating to a sound location determined by azimuth, height, and depth for altering the amplitude and shifting the phase angle of the respective signal on a frequency dependent basis for successive discrete frequency intervals across the audio spectrum to produce a respective modified signal therefrom in response to said sound'position control signal, wherein the amplitude alterations and the phase shifts form a continuous differential between the two channels that varies for each said successive frequency interval of the audio spectrum, said sound processor means shifting the phase angle such that each phase angle shift is different relative to zero degrees, and said first and second channels being maintained separate and apart prior to being fed to the two transducers.
2. The Claim Construction
The first claim at issue of each of the patents is a method claim, while the second claim at issue of each of the patents is a claim to a “system.” After examining the prosecution history, the special master gave the phrase “being maintained separate and apart” its ordinary, literal meaning. He distinguished, however, between the term “following” that appears in claim 1 of the ’462 and the ’860 patents and the phrase “prior to” that appears in claim 7 of the ’462 patent and claim 5 of the ’860 patent.
The special master interpreted “prior to” as simply requiring that the two signals be kept separate and apart “merely immediately before the loudspeakers [i.e., the ‘transducers’] where the signals are clearly separate and apart.” “Following,” however, was deemed more restrictive. The special master interpreted that term to require the two signals to be kept “separate and apart” from each other immediately after the two signals are initially altered.
Because the two channel signals in the accused Spatializer device are combined after their phase and amplitudes are altered, but are separated immediately before they are fed to the speakers, the special master recommended that the Spatializer does not infringe the “following” claims but potentially could infringe the “prior to”- claims. As indicated above, the district court adopted the special master’s recommendations as to the “following” claims but not the “prior to” claims. The district court held that Desper was entitled to summary judgment of non-infringement on the “prior to” claims as well as the “following” claims. On appeal, QSound challenges the district court’s interpretation of both “following” and “prior to.”
DISCUSSION
“The law governing summary judgment is well established.” C.R. Bard, Inc. v. Advanced Cardiovascular, Inc., 911 F.2d 670, 672, 15 USPQ2d 1540, 1542 (Fed.Cir.1990). “Summary judgment is as appropriate in a patent case as it is in any other case.” Id. Under the Federal Rules of Civil Procedure, a motion for summary judgment should properly be granted when “there is no genuine issue as to any material fact and ... the moving party is entitled to a judgment as a matter of law.” Fed.R.Civ.P. 56(c).
The determination of whether an accused product or process infringes a claim of a patent is universally understood to involve two steps. First, we construe the asserted claim to determine its meaning and scope. See Markman v. Westview Instruments, Inc., 52 F.3d 967, 976, 34 USPQ2d 1321, 1326 (Fed.Cir.1995) (in banc), affd, 517 U.S. 370, 116 S.Ct. 1384, 134 L.Ed.2d 577, 38 USPQ2d 1461 (1996). In the second step, we compare the accused product or process to the properly construed claim. See id.
Whether a product or process infringes the properly construed claims of a patent, literally or under the doctrine of equivalents, is a question of fact. See Tanabe Seiyaku Co. v. United States Int’l Trade Comm’n, 109 F.3d 726, 731, 41 USPQ2d 1976, 1981 (Fed.Cir.1997). Often, as in this case, the composition of the allegedly infringing process or product is undisputed. In such a case, literal infringement collapses into claim construction — a matter of law — amenable to summary judgment. See Athletic Alternatives, Inc. v. Prince Mfg., Inc., 73 F.3d 1573, 1578, 37 USPQ2d 1365, 1370 (Fed.Cir.1996).
To determine the meaning and scope of a claim, we first examine the claim language, the specification, and, if in evidence, the prosecution history. See Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1581, 39 USPQ2d 1573, 1576 (Fed.Cir.1996). Extrinsic evidence, that is, evidence outside the record before the United States Patent and Trademark Office (“PTO”), such as expert testimony about how those skilled in the art would interpret certain language in the claim, may also be considered when appropriate as an inherent part of the process of claim construction and as an aid in arriving at the proper construction of the claim, but may not be used to vary or contradict the otherwise unambiguous meaning of the claim. See id. at 1582, 90 F.3d 1576, 39 USPQ2d at 1577. The proper interpretation of a claim is a legal conclusion, over which we exercise plenary review. See Cybor Corp. v. FAS Tech., Inc., 138 F.3d 1448, 1456, 46 USPQ2d 1169, 1174 (Fed.Cir.1998) (in bane) (“[W]e review claim construction de novo on appeal including any allegedly fact-based questions relating to claim construction.”).
I. “Following”
We start first with the claim language itself. See Thermalloy, Inc. v. Aavid Eng’g, Inc., 121 F.3d 691, 692, 43 USPQ2d 1846, 1848 (Fed.Cir.1997) (“[T]hroughout the interpretation process, the focus remains on the meaning of claim language.”) The first claims of both the ’462 patent and the ’860 patent require that the system “maintain[] the first channel signal separate and apart irom the second channel signal following the step of altering the amplitude and shifting the phase” (emphasis added). The plain meaning of “following” is “subsequent to, after in time” or “next after,” depending on the context. Webster’s Third New International Dictionary 883 (1986). The problem in this case is that this definition does not tell us how close in time to the “altering” step the signals must be maintained separate and apart. To answer that question we consult the specifications.
Though not definitive, the specifications support an interpretation that requires the two signals to be maintained separate and apart beginning immediately after the amplitude is initially altered and the phase is initially shifted. The word “following” appears only twice in each of the written descriptions and is not used with reference to the channel signals. (The same is true of the phrase “prior to,” discussed infra.) The drawings, Fig. 16 and Fig. 18a (pictured supra), however, graphically demonstrate that once the two channel signals are separated they are thereafter kept separate. Thus, the drawings support the interpretation that, immediately after the amplitude and phase of the channels signals are initially altered by the filter, they thereafter must be maintained separate and apart.
QSound points to an isolated passage in the written description to support its proposed claim construction that it is only after the alteration of the amplitude and the shifting of the phase by filters and summers are complete that the signals are required to be maintained separate and apart. The passage upon which QSound relies simply indicates that the sound processor “may include some or all of the following circuit elements: filters, delays, [inverters], summers, amplifiers, and phase shifters.” ’462 patent, col. 11, 11. 11-12. The passage sheds no light as to when the signals must be maintained separate and apart.
In contrast, the prosecution history confirms our claim construction. The limitation that the channel signals be maintained separate and apart was not in the original claim language. The original claims of what is now the ’462 patent were rejected as obvious under § 103 in light of British patent No. 942,-459. Tha original application (Ser. No. 07/398,988) was then abandoned in favor of a File Wrapper Continuation (“FWC”) (Ser. No. 07/696,989). See 37 C.F.R. § 1.62 (1997). The limitation that the channel signals be maintained separate and apart was then added in a preliminary amendment dated June 12, 1991. In the remarks accompanying that amendment, the patent applicants’ attorney stated:
In fact, according to the present invention, once the monaural signal is split into the two channel signals, those signals are forever after isolated one from another and are never combined or commingled. Various operations may take place in each channel provided by the present invention, yet the signals being operated upon are never recombined or mixed. This is in direct distinction to the teaching of the British patent....
(Emphasis added.) In his closing remarks, the attorney further stressed in urging reconsideration:
[I]n view of the amendments to the claims hereby, as well as the above remarks, it is respectfully submitted that a method and apparatus for producing two sound signals derived from a single monaural input signal in which an amplitude and phase shift is provided with such signals being maintained separate and apart up until the actual production of the sounds at the speakers, as taught by the present invention and as recited in the amended claims, is neither shown nor suggested in any of the cited references, alone or in combination.
(Emphasis added). Rather than wait for a formal, written response, the applicants conducted a personal examiner interview. In the resulting “Examiner Interview Summary Record,” the examiner indicated that the amended claims “appear to distinguish over art of record in prior case (FR 1,512,059 & B 942,459).” However, the examiner did come up with a new reference on which to base another prior art rejection. Despite this new reference, the examiner indicated that two dependent claims would be allowable if they were to be rewritten in independent form. In response, the applicants abandoned the original independent claims and took what the examiner allowed. The rewritten claims were subsequently allowed and issued as part of the ’462 patent.
The prosecution history of the ’860 patents tells much the same story. The ’860 patent was originally filed as a Rule 60 divisional of the FWC (Ser. No. 07/696,989). See 37 C.F.R. § 1.60 (1997). In a preliminary amendment dated October 31, 1991, after the parent application had been rejected in view of the British patent, the applicants amended all the independent claims to include the limitation that the channel signals be maintained separate and apart. In an office action dated February 5, 1992, the examiner rejected the amended claims as obvious in light of another reference. The applicants’ attorney responded with further amendments to the claims, and accompanying remarks in which the attorney distinguished the claimed invention from the cited reference. This amendment was sufficient to overcome the rejection, and the amended claims were issued as part of the ’860 patent. Thus, in the file history of both patente, the limitation that the channel signals be maintained separate and apart was added to overcome the prior art rejection based on the British reference, and in both cases it succeeded.
QSound does not argue on appeal that its attorney’s comments do not, on their face, limit the scope of the asserted claims. Rather, QSound argues that the prosecuting attorney’s remarks should, not be used to interpret the disputed claim language because the remarks, according to QSound, were both erroneous and extraneous — erroneous because they are contrary to the express teaching of the patent itself and extraneous because they did not become part of the claim. We disagree on both accounts.
Fig. 18a (pictured supra), according to QSound, “proves ... that counsel’s statement was erroneous.” Brief for Appellant at 33. In particular, QSound argues that “[a]f-ter the signals pass through the points labeled 1657 and 1658, figure 18[a] shows that the signals cross, and are commingled, at the point labeled 1659.” Brief for Appellant at 34. This post-hoc argument flies in the face of the entirety of the written description and the operation of a switch as well understood in the art. The symbol for 1659 shows a broken, diagonal line with a continuous, diagonal line passing through the opening therein. This notation is used, as is well known in the art, to indicate that the two conductors within the switch are not connected. The switch, according to the written description, “allows the filter signals to be fed directly or interchanged, to first inputs of summing elements 1660 and 1670.” ’462 patent, col. 13, lines 12-14. Thus, reversible switch 1659 does not, as QSound alleges, “commingle” the two channel signals, but, instead, re-routes the respective signals to either summing element 1660 or 1670 depending on the switch setting. Switch 1659 therefore gives the operator the ability to create a mirror image of the sound illusion by simply flipping the switch. This reading is consistent with the normal operation of a reversible switch. Counsel’s argument to the contrary is disingenuous at best and blatantly false at worst.
Following oral argument, during which counsel’s characterization of the switch was challenged, QSound attempted to bolster its untenable position with a submission of testimony from its expert, ostensibly pursuant to Fed. R.App. P. 28