The opinion of the court was delivered by: GALSTON
This is a patent suit in which the defendants are charged with the infringement of letters patent No. 1,687,510. The patent issued October 16, 1928, on the application of Marvin Pipkin for an improvement in an electric lamp bulb.
The specification describes an improved method in frosting bulbs on the inside, and frosting other thin glassware. Frosting of an electric light bulb on the inside is desirable, since better diffusion with a lower absorption of light is obtained. Moreover, the inside frosting leaves the outside surface of the article smooth, so that it will not collect dirt easily.
The object of the invention was to overcome the fragility of bulbs and thin glassware theretofore frosted on the inside. As recited by the inventor, his invention seems to have been: "I have found, however, that if the bulb is given a further treatment, in which it is subjected to an etching or frosting treatment of lower degree than that to which it was first subjected, it becomes quite strong."
However one may read the specification, and though in the original application method as well as product claims were included, the conclusion is compelling that it was the process which Pipkin deemed to be his invention. The process claims of the patent, however, were rejected and the two claims of the patent are both for a new product. They read:
"1. A glass electric lamp bulb having its interior surface frosted by etching so that the maximum brightness of an ordinary incandescent lamp comprising such a bulb will be less than twenty-five per cent of that of said lamp with a clear bulb, said interior bulb surface being characterized by the presence of rounded as distinguished from sharp angular crevices to such an extent that the strength to resist breakage by impact is greater than twenty per cent of that of the clear bulb.
"2. A glass electric lamp bulb having its interior surface frosted by etching so that the maximum brightness of an ordinary incandescent lamp comprising such a bulb will be less than twenty-five per cent of that of said lamp with a clear bulb, said interior bulb surface being characterized by the presence of rounded as distinguished from sharp angular crevices to such an extent that the strength to resist breakage by impact is greater than forty-five per cent of that of the clear bulb."
These claims are somewhat unusual in their phrasing and content, for it is obvious that by their limitation, if the structure defined could be produced by a method other than by etching, these claims would not be infringed.
The patent was found valid in General Electric Co. v. Save Sales Co. et al. (C.C.A.) 82 F.2d 100. Invalidity nevertheless is asserted here and reliance had on various patents and publications which were not before the court in the Save Case.
The frosting described in the patent is secured by treatment with hydrofluoric acid and ammonium compound. The initial frosting causes an etching or eating out of the surface of the bulb. It is then washed in a tank to remove the frosting solution. Thereafter the bulb is strengthened by an application of a weaker etching solution. In the plaintiff's commercial process the intermediate washing step is eliminated.
The art shows that glassware had been processed in accordance with the principle set forth in this patent. Multiple etching is shown to have been old and the surface of glass thus treated was of necessity, as is stated in the claims, "characterized by the presence of rounded as distinguished from sharp angular crevices."
British patent, No. 166,133, of 1922 relates to screens and sheets for the reception of optically projected pictures, images, and the like. The screen is formed of plate glass and a "satin-surface" is the object sought. The inventor secures this "satin-surface" by applying first a mixture of hydrofluoric acid and an alkali, and "subsequently reducing or clearing fully with hydrofluoric acid, thus producing a finely granulated and slightly diffusive surface exhibiting a satin-like 'sheen' or like effect."
Thus this patent clearly shows the use of a two-shot process of reduction of the frosted surface. Necessarily the resultant physical characteristics were the same as those obtained by the Pipkin process.
Die Glashutte of 1887 contains an article entitled, "Contributions to the Knowledge of Glass Etching" wherein it is said: "It is a priori clear that the frosted appearance of the glass can only arise because the surface possesses many unevennesses lying closely adjacent to one another and which are of such a nature ...