Electric and Musical Industries, Ltd. et al v. Lissen, Ltd. et al

citation(s): (1939), 56 R.P.C. 23 (per Lord Russell of Killowen)

JurisDictioncom.gif (2187 bytes)  Case Comment        1997-2007 Donald M. Cameron




The Decision

At p. 39:

"My Lords, in this case, as in all patent actions in which the validity of the patent is contested, the question of construction is of primary importance, and is necessarily antecedent to the determination of the issues of want of novelty and absence of subject-matter.

The Court of Appeal have stated that in their opinion no special rules are applicable to the construction of a specification, that it must be read as a whole and in the light of surrounding circumstances; that it may be gathered from the specification that particular words bear an unusual meaning; and that, if possible, a specification should be construed so as not to lead to a foolish result or one which the patentee could not have contemplated.  They further have pointed out that the claims have a particular function to discharge. With every word of this I agree; but I desire to add something further in regard to the claim in a specification.

The function of the claims is to define clearly and with precision the monopoly claimed, so that others may know the exact boundaries of the area within which they will be trespassers. Their primary object is to limit and not to extend the monopoly. What is not claimed is disclaimed. The claims must undoubtedly be read as part of the entire document, and not as a separate document; but the forbidden field must be found in the language of the claims and not elsewhere. It is not permissible, in my opinion, by reference to some language used in the earlier part of the specification to change a claim which by its own language is a claim for one subject-matter into a claim for another and a different subject-matter, which is what you do when you alter the boundaries of the forbidden territory. A patentee who describes an invention in the body of a specification obtains no monopoly unless it is claimed in the claims. As Lord Cairns said, there is no such thing as infringement of the equity of a patent (Dudgeon v. Thomson, L.R. 3 App. Cas. 34).”

At p. 41

"I would point out that there is no question here of words in Claim 1 bearing any special or unusual meaning by reason either of a dictionary found elsewhere in the Specification or of technical knowledge possessed by persons skilled in the art. The prima facie meaning of words used in a claim may not be either true meaning when read in the light of such a dictionary or of such technical knowledge; and in those circumstances a claim, when so construed, may bear a meaning different from that which it would gave borne had no such assisting light been available. That is construing a document in accordance with the recognized canons of construction. But I know of no canon or principle which will justify one in departing from the unambiguous and grammatical meaning of a claim and narrowing or extending its scope by reading into it words which are not in it; or which will justify one in using stray phrases in the body of a specification for the purpose of narrowing or widening the boundaries of the monopoly fixed by the plain words of a claim."

 At p. 41-42:

"A claim is a portion of the specification which fulfils a separate and distinct function. It and it alone defines the monopoly; and the patentee is under a statutory obligation to state in the claims clearly and distinctly what is the invention which he desires to protect. As Lord Chelmsford said in this House many years ago: "The office of a claim is to define and limit with precision what it is which is claimed to have been invented and therefore patented" (Harrison v. Anderston Foundry Co., L.R. I App. Cas. 574). If the patentee has done this in a claim the language of which is plain and unambiguous, it is not open to your Lordships to restrict or expand or qualify its scope by reference to the body of the specification. Lord Loreburn emphasized this when he said: "The idea of allowing a patentee to use perfectly general language in the claim and subsequently to restrict or expand or qualify what is therein expressed by borrowing this or that gloss from other parts of the specification is wholly inadmissible" (Ingersoll Sergeant Drill Co. v. Consolidated Pneumatic Tool Co. 25 Reports of Patent Cases, page 61, at page 83). Sir Mark Romer expressed the same view in the following felicitous language: - "One may and one ought to refer to the body of the specification for the purpose of ascertaining the meaning of the words and phrases used in the claims, or for the purpose of resolving difficulties of construction occasioned by the claims when read by themselves.  But where the construction of a claim when read by itself is plain, it is not, in my opinion, legitimate to diminish the ambit of the monopoly claimed merely because in the body of the specification the patentee has described his invention in more restricted terms than in the claim itself." (British Hartford-Fairmont Syndicate, Ld. v. Jackson Bros. (Knottingley), Ltd., 49 Reports of Patent Cases, page 495 at page 556)."

At p. 43

"The Patentees have by this Specification sought to protect a device which they believed their assignor had invented, and they have sought to protect it by claiming a method of adjusting the transmission through the described amplifier (that is, a method of amplification) which employed that device.  Upon discovering that the device had, unfortunately for them been anticipated by Huth (to say nothing of Siemens and Halske), the suggestion is evolved that Claim 1 is not for that which its natural meaning conveys, but for something narrower, the justification for his narrowing of the monopoly being sundry phrases picked here and there from the body of the Specification.

I cannot assent to this suggestion.  It looks to me like throwing scientific dust in the eyes of the court.  To my mind, this is a plain case of plain English, in which your Lordships stand in no need of scientific witnesses or counsel to assist you in arriving at the true meaning of the language used."


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