North American Philips Co. v. Stewart Engineering Co.

319 F. Supp. 335, 1970 U.S. Dist. LEXIS 13408
CourtDistrict Court, N.D. California
DecidedJuly 10, 1970
DocketCiv. A. 42811
StatusPublished

This text of 319 F. Supp. 335 (North American Philips Co. v. Stewart Engineering Co.) is published on Counsel Stack Legal Research, covering District Court, N.D. California primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
North American Philips Co. v. Stewart Engineering Co., 319 F. Supp. 335, 1970 U.S. Dist. LEXIS 13408 (N.D. Cal. 1970).

Opinion

FINDINGS OF FACT AND CONCLUSIONS OF LAW

ZIRPOLI, District Judge.

After consideration of the entire record herein and the final arguments of counsel, the Court makes the following Findings of Fact and Conclusions of Law.

*336 FINDINGS OF FACT

1. Plaintiff, U. S. Philips Corporation (hereinafter Philips), is a corporation of Delaware with offices at 100 E. 42nd Street, New York, New York. It acquired the sole title to the three patents in suit from the original plaintiff, North American Philips Company, Inc., and was thereafter added as a party plaintiff. [Pre-Trial Order, Admitted Facts Section (6), paras. 1, 4, 6, Order for Addition of Parties dated Oct. 7,1969; Stipulation filed August 20, 1969]

2. Defendant Watkins-Johnson Company (hereinafter Watkins-Johnson), is a corporation of California with offices at 3333 Hillview Avenue, Palo Alto, California. It is the successor by merger of defendant, Stewart Engineering Company. [Pre-Trial Order, Admitted Facts Section (6), para. 2; Order for Addition of Parties dated Oct. 7,1969; Stipulation filed August 20, 1969]

3. Defendant, Spectra-Mat, Inc. (hereinafter Spectra-Mat), is a corporation of California with offices at 1240 Highway 1, Watsonville, California 95076. [Pre-Trial Order, Admitted Facts Section (6), para. 3]

A. Nature of Action

4. This action is for infringement of U. S. Patents No. 2,700,000 entitled “Thermionic Cathode and Method of Manufacturing Same” (’000 patent), 2,700,118 entitled “Ineandesible Cathode” (•’118 patent), both issued January 18, 1955, and 3,201,639 entitled “Thermionic Dispenser cathode” (’639 patent), issued August 17, 1965. All three patents relate to tungsten dispenser cathodes, and the ’000 and ’639 patents also relate to methods ■ for their manufacture. Spectra-Mat has been manufacturing and selling tungsten dispenser cathodes in the State of California and elsewhere since its formation in 1963. Watkins-Johnson, and Stewart Engineering Company before it, have been making and selling, for non-government as well as government end use, in the State of California and elsewhere, electron tubes which include tungsten dispenser cathodes purchased from Spectra-Mat. [Pre-Trial Order, Admitted Facts Section (6); paras. 4, 6, 14, 34, 35; PX-2, -3, -4; Cronin Tr. 1240-54]

5. In its simplest form, a “cathode” is an electrode sealed in an electron tube and essential for its operation. When the tube is operating, heat is provided to generate electrons from the cathode. These electrons under the influence of suitable voltages then travel through the tube to another electrode called an anode. The impregnated tungsten dispenser cathodes involved in this litigation are generally used in highly sophisticated microwave vacuum tubes, such as magnetron tubes, traveling wave tubes, backward wave oscillator tubes and klystron tubes. These tubes are widely used in radar systems and for communication, identification, testing and other purposes. The cathode has been referred to as “the heart” of microwave tubes such as magnetrons. [Rittner Tr. 68-70, 244-6; Nowogrodzki Tr. 429-31, 441-3, 449, 451; Cronin Tr. 1226; PX-1F, -44]

B. Scope and Content of the Prior Art

6. The pre-1950 cathodes other than pure metal emitters can be conveniently grouped or categorized in two main classes (a) non-dispenser cathodes and (b) dispenser cathodes. These classes are quite different from one another in structure, mode of operation and uses. [Rittner Tr. 75, 112-6; PX-12B]

1, Non-dispenser cathodes

7. Non-dispenser cathodes are characterized by a short' processing heat treatment significantly above the prescribed operating temperature of the cathode. This “shot of heat” causes a chemical reaction which generates— once and for all — the activator. Thereafter, this activator must be available throughout the cathode’s useful life. There are two subclasses of non-dispenser cathodes: (1) thoriated tungsten cathodes developed about 1913 by Irving *337 Langmuir, and (2) oxide-coated cathodes developed about 1904 — each of which has been used for many years despite serious shortcomings. [Rittner Tr. 76-9; PX-12C, -12A]

8. The thoriated tungsten cathode is generally made from a tungsten wire or filament activated by an extremely thin layer of thorium formed by the reaction of thorium oxide and tungsten. These cathodes can only be operated at high temperatures from 1600° to 1900°C. But it is not feasible to construct heaters capable of maintaining the emitting surface at these temperatures, so thoriated tungsten cathodes are only used in the form of filaments which are heated by passing current directly through the filament. At the usual operating temperature of these cathodes, there is no significant chemical reaction between the thorium oxide and the tungsten, so their principal activation must occur before the tube is put into operation by a flash or shot of heat at about 2200 °C. If the thorium activator is lost during operation of these cathodes, it cannot be regenerated at the normal operating temperature. [Rittner Tr. 76; PX-12C, -17]

9. The oxide-coated cathode generally consists of a thick coating of barium-strontium oxide on a nickel support. It can be made only in limited shapes and dimensions because of drawbacks due to its manufacture by spraying or otherwise depositing a layer of oxide over its entire supporting metal base. These cathodes cannot be made in intricate, specially curved shapes with dimensions to close tolerances, and they cannot be made with emitters of either very small or very large areas. In addition, being a semiconductor type of emitter, as contrasted to a metal emitter, it has a relatively low direct current (D.C.) emission capability which is inadequate for most microwave tubes. [Rittner Tr. 115-8, 164-5; Kelley Tr. 670-2; Cronin Tr. 1214; PX-12A, -13, -14, -15, -16, -43]

10. Oxide-coated cathodes are so different from dispenser cathodes in structure, mode of operation and properties that oxide cathode prior art was of no help whatever in solving the problems which confronted the patentees of the patents in suit. Although this and other prior art was available to Spectra-Mat’s president and his associates when they were attempting to duplicate the Philips impregnated cathode, it is abundantly clear from the record that they received no help from it. [Cronin Tr. 1089-90; Rittner Tr. 111-3, 115-6, 359; Kelley Tr. 955; Nowogrodzki Tr. 507]

11. Oxide-coated cathodes to this day are used commercially where low emission is required, and they are beset with many well recognized problems of long standing. The first problem is the destructable nature of the cathode’s active surface from which the electrons are emitted. This is a particularly serious difficulty when the cathode is subjected to bombardment by ions and electrons resulting in harmful physical and chemical changes in its emitting surface. This bombardment physically dislodges sections of the oxide coating thus destroying the emitting surface, since the oxide cathode is incapable of regenerating these lost oxide sections at normal operating temperatures. Bombardment also results in loss of the activator due to undesirably rapid evaporation. [Rittner Tr. 153-7, 159-65, 247; Nowogrodzki Tr. 452]

12.

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§ 101-103
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Bluebook (online)
319 F. Supp. 335, 1970 U.S. Dist. LEXIS 13408, Counsel Stack Legal Research, https://law.counselstack.com/opinion/north-american-philips-co-v-stewart-engineering-co-cand-1970.