Neff Instrument Corporation v. Cohu Electronics, Inc.
| Decision Date | 11 December 1961 |
| Docket Number | No. 16951.,16951. |
| Citation | 298 F.2d 82 |
| Parties | NEFF INSTRUMENT CORPORATION, Appellant, v. COHU ELECTRONICS, INC., and Neely Enterprises, Appellees. COHU ELECTRONICS, INC., and Neely Enterprises, Appellants, v. NEFF INSTRUMENT CORPORATION, Appellee. |
| Court | U.S. Court of Appeals — Ninth Circuit |
Fraser & Bogucki, by Robert H. Fraser and Raymond A. Bogucki, Los Angeles, Cal., for appellant Neff Instrument Corp.
Lyon & Lyon, by Charles Lyon, Los Angeles, Cal., for appellee Cohu Electronics.
Before BARNES, HAMLEY and DUNIWAY, Circuit Judges.
This is an appeal and a cross-appeal from an action brought in the United States District Court by plaintiff1 for infringement of United States Letters Patent No. 2,832,848 by defendant. In a prior appeal2 this court reversed the entry of a summary judgment by the district court. After a supplemental complaint had been filed and answered, the case was tried and the district court entered a judgment holding the patent valid but not infringed. No issues here involved were present in the prior appeal. Plaintiff appeals from the district court's holding that the patent was not infringed. Defendant appeals from the district court's holding that the patent was valid in law.
Jurisdiction in the district court was found upon Sections 1338(a) and 1400 (b) of Title 28 United States Code. This court has jurisdiction to review the judgment entered by the district court by virtue of Sections 1291 and 1294 of Title 28 United States Code.
The facts are the same for both appeals. The patented device is an electrical signal amplifier which is especially useful in instrumentation systems in which relatively weak signals representing physical phenomena such as temperature, pressure, stress, and vibration must be strengthened, i. e., amplified, for application to output equipment for measuring and recording the phenomena (Ex. 1, R. 409).3
In order to measure each of the desired phenomena, a number of small measuring devices known as transducers may be attached to various parts of the engine being tested. Common types of transducers include thermocouples (for the measurement of temperature) and stress gauges (for the measurement of stress and vibration). The transducers function to generate a small electrical impulse or signal which varies in a manner corresponding to the action of the phenomena being measured. Since the signals emitted by the transducers are so weak as to be unusable directly, an electrical signal amplifier is used to receive the signal from the transducer and to provide a magnified signal which is suitable for application to output equipment such as a recorder, meter, or a computing system.
The patented device here in question is directed to an electrical signal amplifier which has unique capabilities for the amplification of signals in an instrumentation system such as described above. Such an instrumentation presents several problems:
(1) The signals emitted by a transducer generally include a direct current4 component with a relatively constant value and an alternating current component which varies with time. Both signal components must be amplified to produce an output signal faithfully representing the phenomena being measured. Consequently, the ability to amplify direct and alternating signals components is an essential characteristic; the first of three characteristics of the patented amplifier.5
(2) Where signals are simultaneously emitted from a number of separate transducers and individually amplified, each of the individual amplifiers should provide an output signal which faithfully represents but one of the signals emitted by the transducers without interaction with the other of the signals.
Where interconnections exist for the passage of signals between the amplifiers, interaction occurs between the signals. (An interconnection between amplifiers may be made through a "common ground.") The matter is further complicated by spurious signals, which may be generated within these interconnections, appearing in the output amplifier.
To the extent that spurious signals appear at the output of an amplifier, the output signal from the amplifier does not truly represent the phenomena being measured. To overcome this problem, the patented amplifier has an input circuit which is (conductively) isolated from the output circuit, i. e., no electrical connection is established for the conduction of current between the transducers which may be connected to the input circuit and whatever equipment may be connected to the output of the amplifier. This "conductive isolation" is the second of three characteristics of the patented amplifier (R. 61, 103, 169-170).
(3) Where it is necessary to amplify electrical signals with a high degree of accuracy, the output signal from the amplifier must be a faithful replica of the input signal. To achieve the required degree of fidelity in the output signal, it is common to employ a "negative feedback." With negative feedback, a portion of the output signal is fed back into the input circuit in a direction which produces a partial cancellation of the input signal. This practically eliminates any distortion of the signal produced by the amplifier. But where a connection is made between an output circuit and an input circuit the result is that the connection defeats and militates against the isolation of the input circuit from the output circuit — as described in problem (2) above. The third characteristic of the patented amplifier allows the negative feedback without loss of the other characteristics mentioned above.
Therefore, the patented amplifier for the first time provides the following simultaneously:
(1) Amplification of direct current signals;
(2) Isolation of the input circuit from the output circuit; and
(3) Negative feedback from the output to the input circuit.
The patent in question describes and claims an electrical signal amplifier having all three of the above described characteristics. The structure defined in the patent claims is divided into ten elements, although some of the claims are subcombination claims and do not include all ten. The patent (Ex. 1, R. 407) contains a total of eleven claims.6
Electrical signal amplifiers substantially identical to the amplifier described in the patent have been successfully manufactured and sold by the plaintiff since the early part of 1957. On July 3, 1957, after plaintiff had placed its amplifiers on sale, defendant purchased one of plaintiff's amplifiers for investigation by defendant's engineers (Ex. 11, R. 433; Ex. 12, R. 435). A second, improved, amplifier was subsequently purchased by defendant through a third party (Ex. 13, R. 437; Ex. 14, R. 439; Ex. 18, R. 373).
At the time of the first purchase, defendant (who then manufactured amplifiers of another type) had not achieved a finished working model having the desirable characteristics of plaintiff's amplifier. With respect to the characteristics of the patented amplifier in providing simultaneously for the amplification of direct current signals, isolation of the input circuit from the output circuit, and negative feedback to the input circuit, testimony and evidence indicate that both the patented and the accused amplifiers are alike. The description of the operation of the patented amplifier would apply equally well to a diagram of the accused amplifier published by defendant. It is admitted that each of the claims of the patent read on the infringing device.
The district court's judgment held plaintiff's patent to be valid in law but not infringed. The court recognized the characteristics of the patented amplifier but stated:
The court then stated further:
The following dissimilarities were found by the district court: (1) The patented amplifier uses a capacitor 66, the accused amplifier does not; (2) The patented amplifier uses an LC filter, the accused amplifier uses an RC filter; and (3) The accused amplifier uses an output amplifier which is not shown nor used in the patented amplifier.
We first consider defendant's cross-appeal as to the validity of the patent. Defendant's specification of errors relied upon reads as follows:
(1) The district court erred in holding:
"That the subject matter of the patent in suit would not have been obvious at the time the invention was made to the person having ordinary skill in the art to which such subject matter pertains." (Conclusion of Law II.)
(2) The district court erred in holding:
"That the patent in suit and each of the claims thereof is good and valid law." (Conclusion of Law III.)
(3) The district court erred in not finding that the patent in suit was an aggregate of well-known old expedients.
(4) The district court erred in not finding that the patent in suit is invalid and void as each of the claims thereof fails to particularly point out and distinctly claim the subject matter thereof as required by Title 35 U.S.C. § 112.
(5) The district court erred in adjudging:
(Para. 2, Judgment.)
(6) The district court erred in including in its judgment a holding that the patent in suit was valid in view of the holding of noninfringement.
Defendant's primary contention is "that the alleged invention was readily available once one was willing to spend this kind of money for one amplifier." (Op. Br. 5.) It argues that "as the device therefore incorporates an...
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