Mackay Radio v RCA 306 US 86 (1939)

Posted by Anton Hughes on Tuesday, January 03, 2006 with No comments
Citation: Mackay Radio & Telegraph Co v Radio Corporation of America (1939) 306 US 86

Jurisdiction: US Supreme Court

Facts: MR held a patent on a directive antenna system for use in radio communication, having he antenna wires arranged in the form of a V, at an angle determined by the wave length to be propagated, and of a length which is a multiple of half wave lengths. They alleged that this patent was infringed by RCA's antenna which was V shaped, but whose length was multiple of quarter wave lengths and in which the angles of diversion was different to the formula set out in the MR patent. MR also sought to amend the patent after the beginning of proceedings to include wires of any length.

Outcome: Held that RCA's antenna did not infringe on MR's patent, and that MR could not alter their patent to include all lengths of wire to include

Ratio: 1. While a scientific truth or the mathematical expression of it is not patentable invention, a novel and useful structure created with the aid of knowledge of scientific truth may be.

2. Where an invention is a narrow one, a patent therefor is to be strictly construed with regard both to the prior art and to alleged infringing devices.

3. Where the scientific law which defines an invention is expressed in a mathematical formula, it is not permissible to alter the formula to expand the scope of the invention if this alters the nature of the law on which the invention is based.

Relevance: The main relevance of the case is that it is authority for the principle that mathematics is unpatentable subject matter as it is an expression of a scientific truth. An application of mathematics however, may be. This authority was relied on in Benson.

The other stuff about the amendment of the formula is interesting as it delves into the relationship between the discovery on which an invention is based and the invention itself, but is not directly relevant to software patenting (that I can see yet).

Quotes:

Stone J

At 92: "The patent states the mathematical formula by which the desired relationship is secured, which shows that the appropriate angle between each of the antenna wires and their bisector depends upon the wave length to be propagated and the use of antenna wires of a length which is a multiple of half wave lengths."

At 94: "It is plain ... that the Carter invention, if it was invention, consisted in taking the angle of the Abraham formula as the angle between each wire of the V antenna and its bisector."

At 94: "While a scientific truth, or the mathematical expression of it, is not patentable invention, a novel and useful structure created with the aid of knowledge of scientific truth may be.  But we do not stop to solve the problem whether it was more than the skill of the art to combine the teaching of Abraham with that of Lindenblad and others... We assume, without deciding the point, that this advance was invention even though it was achieved by the logical application of a known scientific law to a familiar type of antenna. But this is apparent that if this assumption is correct the invention was a narrow one... and is to be strictly construed with regard both to prior art and to alleged infringing devices. ... [95] Carter's structure was a V antenna having an angle double the Abraham angle and wires containing a multiple of half wave lengths."

At 98: "[W]e think that the attempt to extend the claims, based on the application of the empirical formula, to wire lengths not multiples of half wave lengths, must fail, because such structures are not within the invention described in the application... [99] The claimed use of the empirical formula for the calculation of the angle for wires which are not multiples of half wave lengths long thus involved a departure from what Carter's application had described as his invention, and a contradiction of it.... [100] This use of the empirical formula for a purpose for which it was not devised does not justify our construing the application as though all reference to the Abraham formula had been eliminated and a new and different one expressing a new and different scientific law had been substituted for it... After the present suit was brought the application was altered by amendment so as in effect to wipe out all reference to the scientific law by which Carter's inventionn was defined... These amendements operated to modify the Abraham formula so as to cancel from the application the statement of the scientific law defining the invention. They left as its definition the modified Abraham formula and its counterpart, the empirical formula, stating a different law which their genesis did not authorize"