The opinion of the court was delivered by: BYERS
The plaintiff, as assignee of the patentee, sues in equity for infringement of Flick United States patent No. 1,526,127, issued February 10, 1925, application filed July 10, 1923, for "Coating Aluminum Articles." The claims involved are numbers 5 and 10, namely:
"5. The process of coloring the surface of aluminum, which comprises providing the aluminum with an absorbent and adherent* (electrolytically produced) coating of oxide of aluminum and treating the aluminum with a lake-forming dye."
"10. An aluminum article having on its surface a dense, absorbent and adherent*a (electrolytic) coating of aluminum oxide combined throughout its depth with a lake-forming dye, the coating being resistant to abrasion and to injury by bending the article."
The changes indicated by parentheses were embodied in a disclaimer filed on or about May 27, 1933.
The trial began on June 19, 1933, and closed on June 30th. Argument was had on October 30, 1933, and thereafter the minutes were corrected and final briefs filed.
The purpose of the patent, so far as the process is concerned, is to color aluminum by creating electrolytically, on the surface of the metal, a film into which dye is introduced; the result of the operation of the process is that the metallic surface of the metal is overlaid by a coating which is a combination of the aluminum itself with nascent oxygen electrolytically liberated at the anode of an electric circuit, which anode is the aluminum object itself, and this coating accepts dye of the character referred to in the patent.
That the metal when so colored is rendered widely adaptable for commercial use not previously deemed appropriate, is obvious.
Both parties practice the same process, and the differences, if any, are stipulated to be unimportant; that is to say, an electrolyte composed of about 7 per cent. of sulphuric acid in water is used, and the article upon which the film is to be formed constitutes the anode, and the container of the electrolyte is the cathode in the circuit; an electric current of about 12 to 15 volts, having a current density of from 15 to 18 amperes per square foot of exposed surface, is applied for about forty minutes; the film is thereby created, and the anode is then detached from the circuit, rinsed in clear water and immersed in a coloring solution composed of organic dye in water solution, for such time as may be required -- from one to fifteen minutes -- depending upon the shading desired of a given color, and the dye solution is maintained at a temperature of from 30 degrees to 60 degrees C.
That the practice of the parties is substantially similar was conceded, and what has been said paraphrases the testimony as to the plaintiff's methods; the defendants' practice is not the subject of testimony on the part of any one who has observed it.
The most important issue in the case is whether the sulphuric acid electrolyte, and the current density applied in connection therewith, are within the teaching of the patent.
The defendants argue that, if such practice is within the teaching of the patent, the latter is invalid, for want of invention. If not, that they do not infringe.
In order to understand the principal issue, the Flick patent must be explained.
The recital states that the invention relates to the coating of aluminum, and that the invention has to do with coated aluminum articles, and with a process for coating them; namely, aluminum as such and finished articles fabricated therefrom. Reference is made to the ready acquisition by aluminum of a superficial film of oxide, and that such films or coatings have been proposed for various purposes, such as protection against corrosion, electric insulation, etc., and that the coatings theretofore known were unsatisfactory; the deficiencies are pointed out, namely, lack of adherence, resulting in ready scaling or breaking off of the film from the articles, particularly upon bending, and the patentee says that he has found that such oxide coatings are incapable of being satisfactorily colored because of being thin and non-absorbent.
Flick sought to provide a commercially practical process for forming on aluminum articles a dense, absorbent and adherent coating of aluminum oxide, combined with a coloring substance, which coating is resistant to abrasion and does not crack or peel off upon bending, and is combined throughout its depth with a dye.
In the practice of his invention, so far as the coating or film alone is concerned, the article is employed as an anode in the electrolysis of an aqueous solution containing ammonia, and preferably also ammonium sulphide; the electrolysis of the electrolyte being effected in an electrolytic cell suitable in size and in current capacity to the requirements.
The amount of ammonia or ammonium sulphide in the electrolyte may vary from 2 per cent. to 25 per cent., and the variations are discussed.
The patentee goes on to discuss the voltage required for forming the kind of film desired. He says that satisfactory coatings have been produced with a current density as low as three and as high as twenty-five or more amperes per square inch of the article being coated, and that it is customarily so high that heating of the electrolyte solution cannot be avoided without resort to artificial cooling.
He describes how the article sought to be coated is first cleansed and then made anode in an electrolytic cell containing "* * * an electrolyte such as explained. It has been found by way of a specific example, that by using as the electrolyte an ammonium sulphide solution of the proportions stated, and by using anode and cathode areas of six square inches each, and a potential difference of two hundred and twenty volts between the electrodes, the initial current density is twelve amperes per square inch, and a very satisfactory coating of aluminum oxide is completely formed on the anode article in from one to two minutes. Under these conditions the current density falls off rapidly as the coating is formed and is only about 2.5 amperes per square inch at the end of two minutes."
The aluminum oxide coating so formed is then described as to its appearance and physical qualities.
An advantage of the process, according to the patentee, is the rapidity with which the coating is formed, "whereas in the formation of inferior oxides by the prior art processes extended periods of time may be required."
Coming now to the coloring aspect of the process, the patentee says that his invention contemplates a colored coating for aluminum articles. Incidental to the process that has been explained, different colored coatings may be formed, depending upon the particular electrolyte solution used, and upon the constituent elements which form an aluminum base alloy to be coated. He says: "The use of an electrolyte containing ammonium sulphide gives a coating which is bluish-gray in color. When the article being coated is an aluminum-copper alloy, the coating usually has a decided greenish tinge. By omitting the sulphide from the electrolyte solution, a light cream-colored coating is produced."
He goes on to say that the coating produced by the process is absorbent, which permits permanent dyeing of the coating to produce a wide variety of colors. "There are many dyes, usually acidic in nature, which combine with aluminum hydroxide to form an aluminum salt of the type known as a 'lake.'" Flick says that he has discovered that such dyes may be combined with or absorbed on this oxide coating, either during its formation by adding dye to the electrolyte, or after formation by immersion of the coated article in a solution of a dye. He gives an example of an ammonium sulphide solution to which benzopurpurin is added, which produces a shade of red, while logwood extract added to the electrolyte gives a blue coating, and cochineal a pink coating, etc., "* * * it being understood that by the proper selection of suitable dyes almost any desired color of coating may be produced."
When the dyeing is accomplished in the second operation after the coating has been formed, the combination of a dye with the oxide coating may be facilitated by "heating the dye solution to form from about 50 degrees to 80 degrees C." On this subject, the specification reads: "Reference has been made to dyes which combine with aluminum hydroxide to form an aluminum salt known as a 'lake,' and it has been explained that such dyes may be used to color the oxide coating of an aluminum article. Although lakes are commonly formed by combination with or absorption of dyes by a wide variety of inorganic substances, the lake-forming dyes contemplated by this invention are only those which can combine with or be absorbed by aluminum oxide such as is formed by the process herein disclosed." Further Flick says: "I have described the principle and characteristics of my invention together with the preferred manner of practicing it and several variations and modifications thereof. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than specifically described herein."
Then follow eleven claims, of which but two are here in issue.
While the purposes of the patentee as so disclosed were broad enough to comprehend the coating or film as an end in itself, and therefore to require appraisal as a contribution to a branch of knowledge in which there was already much learning, the more definite purpose of providing a process whereby aluminum and aluminum articles might be colored was clearly and definitely asserted, and marked an advance in territory which had not been explored, much less appropriated; there had been one or two indifferent incursions into it, as will be seen; but the objectives were indefinite or incidental to other purposes.
The limited construction which the defendants would apply to Flick's patent would confine the process to the use of an ammonium sulphide, or ammonia electrolyte, and the article to one which had been colored by that process, and that alone.
From what has been said concerning the practice of the parties, it appears that very much less electric current is employed in connection with the sulphuric acid electrolyte than the patentee found in his specific example, wherein the ammonium sulphide electrolyte was employed. It appears from the testimony that sulphuric acid is much cheaper as an article of commerce than ammonium sulphide; consequently, if there were no other reasons for the present practice -- which there are -- motives of economy would explain the adoption of the sulphuric acid electrolyte.
In the first place, it will be noted that the process as described in claim 5 does not mention the nature or character of the electrolyte to be employed; as the claim has to do only with an electrolytically produced coating, the language of the claim must be considered in connection with the quoted statement of the specifications immediately preceding the claims, concerning the patentee's intention to practice his invention otherwise than as described -- within the scope of his claims.
The plaintiff argues that the proclaimed purpose is broad enough to comprehend the sulphuric acid electrolyte, because an aluminum oxide film is the result of the electrolysis induced in the electrolyte so constituted.
This, the defendants deny.
The course of the defense has not always been easy to follow, but the foregoing statement has been relied upon, in one guise or another, throughout the entire case; if a definite answer to that contention can be given, the controversy will be brought into sharp focus, because, if both electrolytes (the ammonium sulphide and the sulphuric acid) so function that an aluminum oxide ...