Philco Products Ltd. v. Thermionics Ltd.

Philco Products Ltd. v. Thermionics Ltd.
Collection
Supreme Court Judgments
Date
1943-05-17
Report
[1943] SCR 396
Judges
Duff, Lyman Poore; Rinfret, Thibaudeau; Kerwin, Patrick; Hudson, Albert Blellock; Taschereau, Robert
On appeal from
Canada
Subjects
Intellectual property
Decision Content
Supreme Court of Canada
Philco Products Ltd. v. Thermionics Ltd., [1943] S.C.R. 396
Date: 1943-05-17
Philco Products Limited and Cutten-Foster & Sons, Limited (Defendants) Appellants;
and
Thermionics Limited, Canadian Marconi Company, The Canadian General Electric Company Ltd., Canadian Westinghouse Company, Ltd., and Rogers-Majestic Corporation, Ltd. (Plaintiffs) Respondents.
1942: October 13, 14, 15, 16, 19, 20, 21, 22, 23; 1943: May 17.
Present: Duff C. J. and Rinfret, Kerwin, Hudson and Taschereau JJ.
ON APPEAL FROM THE EXCHEQUER COURT OF CANADA
Patent—Infringement of two patents—One held valid and to have been infringed, and one held invalid—Subject-matter—Invention—Anticipation—Alleged illegal agreement in restraint of trade as defence to action for infringement,—Patentee nevertheless entitled to enforce his rights—Combines Investigation Act, R.S.C., 1927, c. 26—Patent Act (D.) 25-26 Geo. V., c. 30—Criminal Code, s. 498.
The action, brought by the respondent Thermionics Limited, is one for the infringement of two patents, the Langmuir and the Freeman patents, acquired by it by way of assignment from the patentees, both patents relating to devices known as vacuum tubes used in radio sets. The other respondents are licensees under the patents so assigned. The appellant, Cutten-Foster & Sons Ltd., was reselling radio tubes, imported into Canada and sold to it by the appellant, Philco Products Ltd., which tubes are alleged to infringe both patents. The Langmuir patent «is entitled "Electron Discharge Apparatus"; and the invention relates to electric discharge devices which are provided with three electrodes, namely, an "electron-emitting cathode", a "co-operating anode" and a "conductor constituting a grid" which regulates the flow of electrons. This "combination" was claimed to include a highly evacuated envelope and structural features which are alleged to be novel and to co-operate to increase the range and capacity of such devices. The Freeman patent had for its principal object the provision for radio service of a tube which may be used in the ordinary receiving and amplifying circuits with alternating current on the filament, thereby eliminating, it is contended, the major alternating current hums or noises which were due to three different factors, i.e., the electrostatic, thermal and magnetic effects. A complete detailed description of the patents is contained in the judgments. The appellants also contended that the assignments of the patents to the respondent, Thermionics Ld., were invalid on the ground that they had been given for an illegal consideration, having been made as a result of an agreement between the respondents whereby they could fix, control and unreasonably enhance the prices at which radio tubes were to be sold to dealers in, and users of, these tubes, thereby restricting competition and detrimentally affecting the public, contrary to the relevant provisions of the Combines Investigation Act and of section 489 of the Criminal Code. The trial judge denied to the appellants the right to adduce evidence to establish facts and things in support of their above-mentioned contentions. The trial judge also held that both patents were valid and that they had been infringed by the appellants.
Held that, as to the Langmuir patent, the appeal of Philco Products Limited should be allowed, and, as to the Freeman patent, the appeal should be dismissed. The Chief Justice and Hudson J. would dismiss the appeal, and Rinfret J. and Taschereau J. would allow the appeal of Philco Products Limited, in connection with both patents (1).
Held that the combination of the features referred to in the Langmuir patent does not afford subject-matter, and, as between the respondents and the appellant Philco Products Limited, the patent granted on Langmuir's application is invalid. The Chief Justice and Hudson J. dissenting.
Held that the Freeman patent was a true combination patent and a novel and useful device, that there was subject matter in it and that the appellants have infringed. Rinfret J. and Taschereau J. dissenting.
Held, also, that, as to the Freeman patent, the defence of anticipation has not been established. Rinfret and Taschereau JJ. dissenting.
Held, also, that the appellant Cutten-Foster & Sons Ltd. was bound by a clause an an agreement entered into by it that it "admits the validity of the letters patent under which radio tubes are or may be licensed", and that, by reason of such admission, the Langmuir patent is valid as between it and the respondents.
Held, further, that the defence, based on an alleged offence against the relevant provisions of the Combines Investigation Act and of section 498 of the Criminal Code, should fail. Assuming the transactions between the respondents or some of them and Thermionics Ltd. were illegal and void, the patents were still vested in them and they were entitled to enforce those rights (Sections 54 to 57 of the Patent Act).
Judgment of the Exchequer Court of Canada ([1941] Exc. C.R. 209) varied.
APPEAL by the defendants from the judgment of Maclean J., late President of the Exchequer Court of Canada[1], maintaining the respondents' action and holding the appellants liable for the infringement of two patents, both relating to radio tubes, and granting relief accordingly to the respondents, of whom the first named sued as owner by assignment of the two patents and the others as licensee thereunder.
Maclean J. held that both patents were valid and that they had been infringed by the appellants. The material facts of the case and the questions at issue are stated in the above head-note and in the judgments now reported.
D. L. McCarthy K.C. and E. G. Gowling for the appellants.
O. M. Biggar K.C. and R. S. Smart K.C. for the respondents, except the Canadian Marconi Company.
W. F. Chipman K.C. for the respondent, the Canadian Marconi Company.
The judgment of the Chief Justice and Hudson J. was delivered by
The Chief Justice.—To deal first with the Langmuir patent, it is important to notice with care what the invention is, as described in the patent. "The present invention", the patent states, "relates to electron discharge devices, for example, discharge tubes having an incandescent cathode". The general character of the devices is described in the specification in these words:—
Devices of this nature are provided) with an electron-emitting cathode, an anode, and a conducting body, commonly termed a "grid", consisting ordinarily of an electrical conductor located between cathode and anode for statically controlling the electrical discharge conditions of the tube.
It proceeds:—
Electron discharge devices as described may be operated at exceedingly high voltages and have a high load capacity. This new apparatus is suited for use in a much wider field than former devices of this nature which were limited to low voltages and very feeble currents.
The combination includes a highly evacuated envelope and structural features which are said to be novel and to co-operate to increase the range and capacity of such devices. Evacuation, it is said, should be carried preferably to a pressure "as low as a few hundredths of a micron, or even lower". In any event, it should be so low that no appreciable gas ionization takes place during normal operation. The various parts of the apparatus are shown as mounted in a tube, or globe, upon a pedestal "similar to the mount employed for incandescent lamps". The cathode consists of a substantially straight filament of highly refractory material, preferably tungsten, mounted between two oppositely disposed supports constituting a frame-work, and upon this frame-work is wound (transversely to the cathode) the wire which constitutes the grid. The turns of the wire are closely adjacent to each other and "very closely adjacent to", but out of contact with, the incandescent cathode. The supporting frame-work for the cathode and grid is attached to a rod, mounted upon the stem of the tube, and adjacent to this framework is the anode, which consists of a wire strung zig-zag over hooks attached to fork-shaped supports and attached to the same rod springing from the stem of the tube. It should be observed parenthetically that the form of neither the anode nor the cathode, as given in this description, is exclusive. Alternative forms are suggested by which the anode takes the form of a plate attached to supports similarly provided and the cathode is "V" shaped. Under these alternative forms, the operation of the apparatus, as regards the matters with which we are concerned, remain the same in principle.
Langmuir admittedly was the first to propose vacuum tubes in which the removal of gases from the envelope was carried to the degree described in this specification. The terms "highly exhausted tube" and "highly rarefied tube", which had been used by scientists and engineers for some years before 1913, the date of Langmuir's invention, conveyed no idea of such a degree of exhaustion, which, by the methods of evacuation then available, could not have been achieved. The advantages of the hard valve, or the hard tube, meaning a highly exhausted valve, are well recognized, one of the most important, perhaps the most important, being that the removal of the residual gases by the methods initiated by Langmuir got rid of a pronounced lack of uniformity in operation, which was encountered in tubes of the soft variety, and made possible the use of tubes carrying current of great magnitude, as well as of exceedingly high potential. About this there is no dispute and, simultaneously with the patent now in question, Langmuir applied for and obtained a patent for his highly exhausted tube which has expired.
The invention of the hard valve brought about a revolution in the radio art. On behalf of the appellants it is contended that the value of the apparatus now in question is almost entirely due to the fact that such a valve is employed and that beyond this Langmuir's combination involves no invention. On the other hand, it is contended that by this apparatus, and especially by its novel features, the advantages of the hard valve can be realized to a degree not possible through any apparatus previously known.
The features of the apparatus, which are emphasized in the argument of the respondents, are:
(1) The construction of the grid consisting of a wire, which may be very fine, wound upon a frame-work, which may be made of a non-conducting material, or of metal, in turns closely adjacent to one another.
(2) The position of the filament which is supported by the two ends of the same frame that supports the grid and is surrounded by the turns of the wire constituting the grid, but not in contact with, though closely adjacent to it.
(3) That all the electrodes, the cathode and the grid (that is to say, the frame which supports the cathode and the grid), and the anode (or the supports to which the anode is attached) are mounted upon a single pedestal in such a manner that sufficient rigidity may be secured to protect each and all of the parts of the apparatus against material shocks, or electrical stresses, having a tendency to bring the separated parts of the apparatus into contact with one another, or to alter the relative position of one part in respect to any other.
As we have seen, it is explicitly stated in the specification that the electron discharge device described may be operated at "exceedingly high voltages" and have a "high load capacity"; the evidence supports this averment.
It is also said that this new apparatus is adaptable for use in a much wider field than former devices of the same nature which were limited to low voltages and very feeble currents.
There is, moreover, a statement at the end of the specification that the apparatus may be used to transmit currents limited in potential only by the dielectric strength of the tube and the mechanical strength of the parts subjected to static forces; the evidence establishes this.
I think the evidence sufficiently supports the proposition that such a closely wound grid in close proximity to the cathode can be employed to obtain a high magnification of the plate current; in other words, that a slight proportionate increase in the potential applied to the grid may cause a vastly greater proportional increase in the value of the plate current; and there is evidence that it may be used to obtain a high load capacity and high magnification of the plate potential.
It is indisputable that the form of grid adapted by Langmuir was entirely new and I cannot accept the proposition that the utility of a closely wound grid of this type placed in close proximity to a cathode, as Langmuir places it, must have been obvious to any radio engineer at the time; nor can I think that the idea itself of using a grid of that type can be said to have been obvious. It seems to me to be too clear for discussion that the grid was a useful improvement and that employed in the manner prescribed by the specification it would co-operate with the highly evacuated envelope to produce most important results. I cannot reach the conclusion that Langmuir's patent has no subject matter.
As to Freeman and Wade, Freeman's invention was made in August, 1921. As a rule, up to that time the heat supplied to the cathode had been derived from a direct current storage battery known as A-battery. There was a wide and insistent demand for some plan by which this battery might be dispensed with and the alternating current of the ordinary electric light circuit be utilized. Such alternating current was then, as now, supplied between 25 and 60 cycles. The application of this current to the tubes of that time produced a loud humming noise in telephone receivers and loud speakers, and Freeman devoted himself to designing a cathode and connections by the use of which this fault might be corrected.
There were then two common types of cathode. In one, the electrons were emitted from the incandescent surface of a refractory conductor, or filament, directly heated by current from an A-battery. In the other, an A-battery also supplied direct current which heated a conductor and from this conductor heat for the cathode was indirectly derived. It seems to be generally admitted that the second type possessed advantages over the first in securing greater uniformity of emission throughout the whole surface of the cathode and thus, in considerable degree, avoiding undesirable irregularities in the electrical field between the anode and the cathode.
When it was attempted to utilize the alternating current of the electric light circuit for heating the filament, the humming noises mentioned were so pronounced that the necessity of discovering some means of getting rid of these noises was at once evident. Freeman ascertained that these noises had three distinct sources, which are conveniently designated as magnetic, electrostatic and thermal. The specification states:
The principal object of our invention is to provide a device of the character described which may foe employed for detecting, amplifying or rectifying alternating currents and which embodies a cathode structure adapted for excitation from a source of low-voltage, commercial-frequency alternating-currents without the introduction of the alternating-current noises heretofore observed in the operation of such devices.
***
Heretofore, it has not been practical to employ alternating currents for the excitation of the cathode or filament of a receiving or amplifying tube for the reason that such currents introduce variations in (the plate current of the tube. Such variations are thought to be due to the following causes:
1. The variations in the intensity of the magnetic field established by the alternating currents traversing the filament, thereby resulting in a variable deflection of the electron stream emanating from the filament;
2. The variations in the electric field around the filament which are caused by the reversals in the potential distribution along the filament;
3. The variations in the emissivity which are caused by the alternate heating and cooling of the filament.
We have found that the desirable results outlined hereinabove may be obtained by applying a cathode construction having an operating cathode surface which has no fall of potential along its surface, that is, a so-called "equipotential surface". Such cathode surface may be rendered thermionically active in a number of different ways, as by subjecting the same to heat or to an electron bombardment. In one form of embodiment of our invention, we provide a cathode construction comprising a central heater element and a co-operating equipotential cathode surface which is positioned immediately adjacent to the heater element. The thermal energy of the heater element may foe transferred to the cathode surface either by conduction or by radiation.
There can be no doubt that by Freeman's combination these noises from all the sources are for practical purposes sufficiently suppressed. By giving to the cathode a substantial mass, a temperature which is virtually constant is maintained in it. As to magnetic hum, the legs of the U-shaped wire are so close together that the opposed magnetic fields go far to cancel each other; and Freeman has by his device succeeded in reducing the effect of these fields to a point where it ceases to be of practical importance. Electrostatic hum disappears, the evidence shows, because Freeman's arrangement affords an effective shield against the electrostatic effects of the alternating potential.
I agree with the learned President of the Exchequer Court of Canada that the defence of anticipation has not been established and I think it unnecessary to add anything to his discussion of that branch of the defence.
The question of substance is: is there subject matter? Freeman, it must be remembered, was not engaged in a scientific investigation. He was trying to find a practical method for getting rid of the noises attending the use of alternating current for heating the cathode. He, of course, possessed the knowledge of scientific principles that we should naturally ascribe to any competent radio engineer; but the practical difficulties were stubborn. The primary object of the current was to produce the emission of electrons from the cathode by the agency of heat; and the heat generated by the current must have the required effect upon the cathode surface. At the same time the flow of electrons must be protected from disturbance due to the magnetic and electrostatic fields set up by the alternating current. This practical problem Freeman succeeded in solving.
The learned President says:—
There can be no doubt that it was obviously desirable that generally radio receiving tubes be operated, if possible, by commercial alternating current, and apparently that was an object that engaged the attention of prominent workers in the art, prior to the date of Freeman. Freeman was the first to disclose a device which could use alternating current and at the same time eliminate the major alternating current hums or noises, and his device has been almost universally used for the purposes described and directed by him. It seems to me that a very strong case has been made for sustaining the validity of this patent. My conclusion is that Freeman is a true combination patent, a novel and useful device, almost universally used in all receiving and amplifying radio circuits using alternating current, and apparently it solved problems which were recognized, the solution of which was deemed desirable and sought for by others, and that there is subject-matter in Freeman.
With this I agree.
I am also satisfied with the conclusions of the learned President in respect of the issue of infringement and with his reason in support of those conclusions. I ought perhaps to say explicitly that I think the learned President has quite satisfactorily dealt with the argument based upon the Torrisi patent.
I now come to the defence based upon the Criminal Code. Paragraph 7 of the statement of defence is in the following words:
The assignments by which the plaintiff, Thermionics Limited, purports to have acquired and holds the patents in suit are invalid because they were given for an illegal consideration, having been made in pursuance, or as a result of an agreement between or among the plaintiffs or some of them, whereby the said plaintiffs fix, control and unreasonably enhance the prices at which radio tubes are sold to dealers in and users of the said tubes, thereby restricting competition and detrimentally affecting the public, all of which is contrary to the provisions of the Combines Investigation Act, R.S.C., 1927, chap. 26, section 2, and amending Acts, and The Criminal Code, R.S.C. 1027, chap. 36, section 498.
The respondents put in evidence the following exhibits in support of the title of the patents in suit:
Exhibit no. 3
Assignment, dated January 2, 1936, of Langmuir patent 212,366 and other patents from Canadian General Electric Company, Limited, to Thermionics Limited, for consideration of one dollar.
Exhibit no. 4
Assignment, dated January 2, 1936, of Freeman and Wade patent 265,517, and other patents from Canadian Westinghouse Company, Limited, to Thermionics Limited for consideration of one dollar.
Exhibit no. 5
License agreement, dated January 2, 1936, from Canadian General Electric Company, Limited, to Thermionics Limited, granting licenses under "all present and future patents" of Licensor and Radio Corporation of America, relating to radio tubes, providing for and limiting the assignments of all patents, including the Langmuir patent in suit, and cancelling many other recited agreements.
Exhibit no. 6
License agreement, dated January 2, 1936, from Canadian Westinghouse Company, Limited, to Thermionics Limited, granting licenses under "all present and future patents" of Licensor and Radio Corporation of America, relating to radio tubes, and providing for and limiting the assignment of all patents, including the Freeman and Wade patent in suit, and cancelling many other recited agreements.
Exhibit no. 7
Admission by appellants, among other things that defendant Cutten-Foster & Sons, Limited, a jobber and one of the appellants, entered into a licensed radio tube sales agreement with the plaintiff Canadian Marconi Company, as of January 3, 1938, executed February 28, 1938. Exhibit no. 9
The Cutten-Foster agreement, identified in exhibit 7
The Cutten-Foster agreement in question was entitled "Licensed Radio Tube Sales Agreement (Jobbers)" and defined, among others, the following terms as a basis upon which radio tubes would be furnished by Canadian Marconi Company, Limited, to Cutten-Foster & Sons, Limited.
It was recited that
"The Manufacturer is engaged in the business of manufacturing and/or selling Thermionic devices * * * hereinafter known and described as 'Radio Tubes';
"All said Radio Tubes are covered by various Letters Patent of the Dominion of Canada owned or controlled by Thermionics Limited";
"The Licensed Jobber desires to become an authorized) jobber of the Manufacturer for the sale only of licensed Radio Tubes in accordance with the license terms and conditions applicable to the same";
(1) "The Manufacturer agrees to sell and the Licensed Jobber agrees to purchase such Radio Tubes";
(4) "The Manufacturer reserves the right at any time to change or modify the list prices, net prices or terms to the Licensed Jobber and/or dealers in respect of Radio Tubes merchandized by the Manufacturer";
(5) " The Licensed Jobber agrees to accept its appointment as a jobber licensed for the sale of only such Radio Tubes as are manufactured in accordance with. * * * the manufacturing patent license enjoyed by the Manufacturer and will purchase only such tubes as are so licensed. The Licensed Jobber * * * will not sell * * * any licensed Radio Tubes at less than such net prices to dealers, service men and licensed amateurs as may be approved from time to time by the Manufacturer, nor will the Licensed Jobber sell to any customers * * * at less than such list prices as from time to time may be approved by the Manufacturer; * * * Any price lists * * * issued * * * by the Licensed Jobber shall contain the list prices only of licensed Radio Tubes as from time to time approved by the Manufacturer."
(6) "* * * The Licensed Jobber admits the validity of the Letters Patent under which said Radio Tubes are or may be licensed * * * and admits that all Radio Tubes manufactured in accordance with said Letters Patent are subject to the limited licenses set forth on the labels attached thereto, and to the conditions set out in this agreement or in the Manufacturer's patent license agreement."
The appellants' counsel, being called upon to state the facts which he proposed to establish under the plea based upon the Combines Act and the Criminal Code (para. 7), stated it was his purpose to prove that:
before the execution, of the agreement in 1936, these four people were exercising their rights under their patents and in open competition. But the result of the agreement was to put the fixing of prices of all the radio tubes made in Canada in the hands of one person, who as a matter of fact, receives no benefit from it, because he gets no royalties except a small royalty from one,—who fixes the price of all radio tubes in Canada and entirely eliminates all competition. that they are the only manufacturers in Canada; that in 1936 they combined and put the right and the power to fix prices in Thermionics Limited, to whom they assigned their patent rights; and that that company, controlling as it does every manufacturer in Canada, has fixed prices, has fixed prices not only to the manufacturer but also to the retailer and the Jobber. Therefore I say that of itself is an infringement not only of the Code but also of the Combines Investigation Act.
The appellants contend that, as a result of the ruling of the President of the Exchequer Court of Canada, they were denied the right to adduce evidence to establish inter alia the following facts and things:
That the respondents, then in open competition, entered into a combine to create a holding company for all of their patents on radio receiving tubes,
That they granted, licenses to manufacture radio tubes only to three members of their own group, 90 that all radio tubes manufactured in the Dominion are limited to these sources,
That there was no consideration for the assignments of the patents on radio receiving tubes other than the illegal combine licenses,
That the respondents jointly fixed the prices of all radio tubes manufactured in the Dominion,
That the respondents kept no records of their price fixing,
That the respondent, Canadian General Electric Company Limited, used the respondent, Thermionics Limited, as a medium to bring patent suits against its competitors without prejudicing its own sales,
That practically all the research and patents which were pooled by the respondents were derived from their corresponding United States companies,
That they eliminated all competition and stifled trade to the detriment of the public, all contrary to the Combines Invvestigation Act and the Criminal Code,
And that the assignments upon which the respondents base this action were founded solely upon illegal agreements and combines.
The facts relied upon by the appellants beyond doubt point to the conclusion that the respondents had entered into an agreement to restrict competition among themselves in respect of radio tubes; and I shall assume that where A and B enter into an agreement to suppress competition in respect of articles of commerce they do not escape the provisions of section 498 of the Criminal Code merely by reason of the fact that these articles of commerce are protected by patents. I shall assume further that the learned trial judge ought to have permitted the appellants to proceed with evidence establishing the existence of such a combine, that is to say, a combine constituting a criminal offence under section 498.
I find myself faced with this difficulty. Prior to the arrangements of 1936, which are impeached by the plea? of the appellants, the Langmuir patent was vested in the General Electric Company—in point of fact the Canadian patent was issued to the Canadian General Electric Company—and the Freeman patent was vested in the Westinghouse Company, having been issued to that company. The illegal combination, assuming it to have been such, to which these companies were parties, did not effect a forfeiture of the statutory rights under the patents. Assuming the transactions between these companies and Thermionics Ltd. were illegal and void, the patents were still vested in them and they are, I think, entitled to enforce those rights. By sections 54 to 57 of the Patent Act, the patentee, as well as those claiming under him, is entitled to recover damages sustained by reason of the infringement, as well as, in a proper case, to an injunction. On this ground I am constrained to the conclusion that the defence embodied in paragraph 7 fails.
The appeal should be dismissed with costs.
The judgment of Rinfret and Taschereau JJ. was delivered by
Taschereau J.—This is an action for infringement brought by Thermionics Limited, a patent holding company. By order of the Court, Canadian Marconi Company, Canadian General Electric Company, Canadian Westinghouse Company, and Rogers Majestic were added as plaintiffs.
The first of these patents, dated August 30th, 1921, bears no. 213,178 and is called the Langmuir patent; the second one, which is no. 265,517, dated November 2nd, 1926, has been referred to throughout the proceedings as the Freeman patent. Both relate to devices known as vacuum tubes used in radio sets.
In their statement of claim the plaintiffs allege that the defendants, the Philco Products Limited, and Cutten-Foster & Sons Limited, both having their head office in the city of Toronto, have infringed the rights of the plaintiffs under the two above-mentioned patents: the defendant Philco Products importing into Canada, and selling through Cutten-Foster & Sons, and this latter defendant re-selling in the ordinary course of business radio tubes of the types nos. 41E, 75, 78E, 6A, 7E, known as Philco tubes, which infringe both letters patent, and also Philco Radio tubes type 84 which infringe letters patent no. 265,517. The late president of the Exchequer Court of Canada came to the conclusion that both patents were valid, and that they had been infringed by the appellants.
As to the Langmuir patent, the appellants submit that it does not disclose any novel patentable subject-matter, that the claims in suit are anticipated by the prior art, and that there has been no infringement. Their submission as to the Freeman patent, is that Freeman did not do more than apply the knowledge common in the art, that it contains no subject-matter, and, as in the first patent, they also submit that there is no infringement.
Dealing first with the Langmuir patent no. 213,178, which is entitled "Electron Discharge Apparatus", and which relates to vacuum tubes, used in radio sets, it is necessary, I think, to indicate the history of the development of these vacuum tubes, for a better understanding of the case.
The early discoveries which lead to their creation go as far back as the beginning of this century. The first audion detector was operated with a Bunsen Burner, the flame of which heated salt in a small cup, with the result that small particles of the sodium were thrown carrying electric charges to an upper platinum wire. It was soon found to have great practical disadvantages. Deforest invented a new type of detector. In an ordinary incandescent lamp he placed a filament (cathode), which when heated gave off small particles of ions of metal or carbon, which were bombarded on a sheet of platinum (anode) placed very near the filament. This detector, based on the same principle as the previous one, constituted an improvement, but it did not obviate all the difficulties. The electrons were received only on the vertical plate placed on the side of the cathode, and it followed that all those projected in other directions were lost inside the lamp.
In order to improve this device, Fleming thought of putting a cylinder of platinum around the filament, thus allowing the anode to fulfil its role in a much more efficient way. This new tube was called the "Fleming Oscillation Valve". At this state of the development of the art, these tubes were, therefore, merely composed of a lamp in which were found a filament or "cathode" (negative pole) from which there was a flow of electrons to the cylindrical "anode" (positive pole). Deforest, after substituting nickel to platinum for the "anode", found that if a "grid" of platinum wire were placed between the anode and the cathode, and properly loaded with electricity, the flow of electrons would become much more regular, and the efficiency of the tube greatly increased.
The next step was made by Langmuir. The improved Deforest Tube could furnish only a low voltage on account of the gas accumulated in the tube. On the 11th of May, 1920, Langmuir obtained patent no. 200,061 which is not the patent in suit. In his specification he says:
My present invention comprises improvements in electron discharge apparatus having a high load capacity and operable with the highest voltages. The novel features of my invention will be pointed out with greater particularity in the appended claims.
The drawings accompanying the specifications show that in the tube are found an "anode", a "cathode" and a "grid" between both to regulate the flow of electrons. However, the claims make no mention of the grid. Claim no. 9 reads as follows:
9. A discharge tube having a cathode adapted to emit electrons, and anode adapted to receive electrons and tube walls fashioned or shaped so as to permit the free passage of a useful proportion of said electrons from cathode to anode, the gas content or residue of said tube and the relation of the parts of the tube being such that the tube is capable of operation with stable and reproducible results substantially unaffected by positive ionization and fluorescence with currents of at least 5 milliamperes and with voltage of at least 200 volts.
This patent, which expired in 1938, was properly called "the high vacuum patent". The tube did not contain any new devices, but, its capability of operating at a very high voltage and high load capacity, depended upon its evacuation to the degree specified in the patent. It is Langmuir himself, who said, speaking of this patent:
Further investigation showed that with the elimination of the gas effects, all of the irregularities which had previously been thought inherent in vacuum discharges from hot cathodes were found to disappear. In order to reach this condition, however, it was not sufficient to evacuate the vessel containing the electrodes to a high degree, but it was essential to free the electrodes so thoroughly from gas that gas was not liberated from them during the operation of the device. It was also necessary to free the glass surfaces very much more thoroughly from gas than had been thought necessary previously. It is under these circumstances and with the above-described development of the art, that Langmuir applied for the first patent in suit, which was granted on the 30th of August, 1921. This patent is called the "Electron Discharge Apparatus".
In his specifications, Langmuir says:
Devices of this nature are provided) with an electron-emitting cathode, an anode, and a conducting body, commonly termed a "grid", consisting, ordinarily of an electrical conductor located between cathode and anode for statically controlling the electrical discharge conditions of the tube. Electron discharge devices as described may be operated at exceedingly high voltages and have a high load capacity. This new apparatus is suited for use in a much wider field than former devices of this nature which were limited to low voltages and very feeble currents.
The present invention comprises various structural features of novelty which co-operate to increase the range and capacity of a device of this type. For example, in accordance with my invention the grid is supported on a frame-work in such manner that mechanical displacement of the grid by static strains or by mechanical shocks cannot easily occur. Other features of novelty are pointed out with particularity in the claims.
Claims 2 to 5 which are the claims on which the plaintiffs rely in their particulars of breaches are as follows:
2. The combination of a highly evacuated envelope, and electron-emitting cathode, a co-operating anode, rods spaced apart and adjacent said cathode, a conductor constituting a grid supported by said rods, and having a plurality of sections transverse to said rods, and external connections for said electrodes and said grid.
3. An electron discharge apparatus comprising an evacuated envelope, an electron-emitting cathode, a co-operating anode, a frame-work spaced about said cathode, and a conductor mounted thereon closely adjacent said cathode.
4. An electron discharge apparatus comprising an evacuated envelope, a refractory conductor, connections for transmitting energy to incandesce said conductor, bars located on opposite sides of said conductor, a wire wound with closely adjacent turns on said bars to constitute a grid, but out of contact with said incandescing conductor, a second set of bars closely adjacent to the first set but insulated therefrom and a conductor constituting an anode mounted thereon in a plane substantially parallel to said grid, and leading-in conductors to said grid and anode.
δ. A vacuum discharge tube comprising a highly evacuated envelope, a cathode adapted to be heated, a co-operating anode, a frame-work located adjacent thereto, a conductor mounted thereon, and located between the cathode and anode, and external connections for said electrodes and said conductor.
It is clear, I think, that what is claimed by this patent is a "combination" composed of a "highly evacuated envelope, and electron-emitting cathode, a co-operating anode", and a "conductor constituting a grid". I have no trouble in coming to the conclusion that the various elements used in the construction of this "Electron Discharge Apparatus" are contrivances that were known long before this Langmuir patent was issued.
Deforests filament in the incandescent lamp, bombarding electrons on a circular sheet of platinum as developed by Fleming, by many years anticipated the description of the devices given in Langmuir's patent; and theoretically, the "grid" later discovered by Deforest and placed between the anode and cathode to regulate the flow of electrons, clearly is a bar to Langmuir's claims of novelty. As to the highly evacuated envelope, it was the subject-matter of the patent issued to Langmuir himself under no. 200,061 on the 11th of May, 1920, and it was as a result of this former discovery that it has been made possible to obtain an electron discharge apparatus having a high load capacity and "operable with the highest voltages", as it has been said by Langmuir speaking of his 1920 patent.
The grid has been the subject of much discussion at the hearing, and with the highest respect, I am unable to agree with the conclusions of the learned president. The only descriptions of the grid, which may be found in the claims on which the respondents rely, are the following:
(a) (claim no. 2) A conductor su