Becker v. Webcor, Inc.
| Decision Date | 05 May 1961 |
| Docket Number | No. 13172.,13172. |
| Citation | 289 F.2d 357 |
| Parties | Harry W. BECKER, Plaintiff-Appellant, v. WEBCOR, INC., Defendant-Appellee. |
| Court | U.S. Court of Appeals — Seventh Circuit |
Sam Kurlandsky, Chicago, Ill., for appellant.
Watson D. Harbaugh, Harbaugh, Rummler & Snow, Evanston, Ill., for defendant-appellee.
Before HASTINGS, Chief Judge, and SCHNACKENBERG and CASTLE, Circuit Judges.
This is an action for patent infringement brought by Harry W. Becker, plaintiff-appellant, against Webcor, Inc., defendant-appellee. The district court found the patents in question to be invalid and not infringed and rendered judgment in favor of Webcor. This appeal followed.
Plaintiff Becker is the owner of the two patents in suit, No. 2,595,443 (No. -443) filed March 14, 1946 and No. 2,595,444 (No. -444) filed June 26, 1946. Both patents were issued to Becker on May 6, 1952.
The two patents relate to electronic audio amplifiers and are primarily concerned with the electrical circuitry in the power output stage. No. -443 discloses a single tube circuit, the one principally considered in this action, in which all claims are in issue. No. -444 discloses a double tube circuit which shows the use of the Becker circuit of No. -443 in a conventional push-pull relationship, in which only claim 3 is in issue.
Plaintiff Becker is an individual residing in Skokie, Illinois and is self-employed as a consultant and designer of various types of radio and television equipment. Defendant Webcor is an Illinois corporation with a place of business in Chicago, Illinois and since May 6, 1952 has made, used and sold a wide variety of amplifier circuits.
Electronic audio amplifiers are a part of a well-developed art. It has been recognized for many years in the art that such amplifiers introduce distortion into the signal being amplified. The result has been that the output signal differs with respect to the input signal. This is due to the fact that vacuum tubes are not perfect devices and introduce into the signal various order harmonics which distort the output signal. This distortion produces an unpleasant effect upon the listener.
Stated in another way, harmonic distortion is that undesirable distortion of the signal being amplified which arises from the inefficiencies of the amplifier and is manifest as spurious frequencies which are the multiples of the frequency being amplified. Such distortion is reduced by inverting the phase of the distortion and feeding it back into the signal amplification path to cancel itself. As a result some loss of amplification of the main signal occurs.
The common purpose of all the circuits brought to the trial court's attention is to improve reproduction fidelity by the reduction of harmonic distortions occurring in the power stage of a signal amplifier.
There are two identifiable prior-art ways of reducing distortion. One is by the "push-pull" method used only in double tube amplifiers, and the other is by "inverse feedback," commonly referred to as "negative feedback," used in all types of amplifiers, both double tube and single tube.
One of the earlier disclosures of negative feedback was in the Black United States Patent No. 2,102,671 issued in 1937. Black's negative feedback consisted of taking a portion of the distorted output of the amplifier and reintroducing it into an input stage of the amplifier in such relationship to the input signal that the portion of the signal fed back tended to cancel a portion of the distortion normally occurring in the amplifier, as well as a portion of the fundamental signal, with the result that overall distortion was reduced.
The prior art disclosed the true pushpull circuit utilizing two separate vacuum tubes. In the push-pull circuit even harmonic distortion components of the current produced by the two tubes tend to cancel, while the fundamental and odd harmonics tend to add. Because the second harmonic component is by far the most powerful of all the distortion components, its cancellation effects a substantial reduction in overall distortion and a substantial improvement in amplifier output, while the extremely weak higher harmonic components do not materially affect the signal.
Becker claims that with the circuit he designed, as described in the patents in suit, he was able to effect a reduction in the most important source of distortion, the second harmonic, in a manner similar to that obtained with the two-tube push-pull circuit of the prior art without the high signal loss resulting from the use of negative feed-back as in the Black invention. He characterized the operation of his amplifier as producing a "push-pull effect," referred to in the trial as the "Becker effect."
Becker contends his No. -443 discloses and claims the original Becker circuit employing a single output tube. He urges that his No. -444 embodies the basic Becker concept of his No. -443, but further discloses its application to a true push-pull circuit using two amplifier tubes. He asserts that his inventions satisfied a long felt need in the highly developed and competitive amplifier industry by providing higher fidelity at low cost.
Becker charges Webcor infringed all claims of his No. -443 by its amplifier ex-emplified by Webcor Model 100-621; claims 1, 3 and 5 of No. -443 by amplifiers exemplified by Webcor Models 100-601 (and other listed models); and claim 3 of No. -444 by amplifiers exemplified by Webcor Models 333 (and other listed models).
The prior art relied upon at the trial was:
United States Patents Black Patent No. 2,102,671, issued December 21, 1937 Cunningham Patent No. 2,429,124 issued October 14, 1947 Foreign Patents Swiss Patent No. 216,071, issued November 1, 1941 French Patent No. 806,775, issued October 5, 1936 British Patent No. 541,260 issued November 15, 1941 Publication Everitt, Communication Engineering 1937, page 439
The Black, French and British patents were not cited by the Patent Office during the prosecution of the patents in suit.
In order to assist the trial court in identifying the elements of the circuits under consideration, a master diagrammatic scheme of the format circuitry was agreed upon and furnished to the court. It was included in the briefs on appeal. Likewise, the format circuits of the accused devices, the patents in suit and the prior art were agreed upon, with certain exceptions, and furnished to us for comparative purposes. The prior art patents are before us.
Plaintiff Becker testified on his own behalf and presented as his expert witness Dr. William L. Everitt, Dean of the School of Engineering at the University of Illinois. Webcor introduced as its expert witness Dr. John A. M. Lyon, Professor of Electrical Engineering at the University of Michigan. Webcor also introduced the testimony of Oscar A. Pearson, its vice-president in charge of research and development, and that of Dr. Richard K. Brown, Professor of Electrical Engineering at the University of Michigan.
Shortly before trial Becker shipped his sole remaining model of the patent circuit outside the jurisdiction of the court. The patents in suit give no values for the circuit components, and Becker could not remember the values he used in the models built by him. Becker made no tests for the court on the circuits disclosed in his patents.
The only tests Becker made were upon accused circuits of Webcor which were shown to be different in certain respects from the Becker circuits. A series of interparty tests were made by the experts employing the test technique referred to as the "Everitt shunt." During the trial Webcor's expert made certain ex parte tests using a modified test procedure, the "Lyon Compensating Impedance."
At the trial, the two opposing experts testified at great length on the procedures used in the various tests, the results obtained and their relationship to the Becker and accused circuits. Lyon testified as to the circuits shown in the prior art. Each expert is admittedly qualified in the field of electronics and demonstrated a high degree of proficiency in the area surrounding the circuits in question. Many of their findings and conclusions were opposite in character, and each generally tended to support the contentions of his respective client.
Everitt concluded that the accused circuits were almost identical to the Becker circuits and that the only differences were minor in character and did not affect the essential operation of the circuits....
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