San Diego Law Review

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In 1954 John Adkins applied for a patent on his plan for a more accurate gyroscope which he had developed soon after being hired by the Lear Corporation. Lear and Adkins entered into a licensing agreement in 1955 in which Lear agreed to pay royalties on Adkins’ idea until the patent application had been refused or the patent was held invalid. In 1957, after Adkins’ patent application had been rejected twice, Lear stopped paying royalties on some of the gyroscopes; two years later it stopped payment altogether. Adkins obtained his patent in 1960 and thereafter sued for royalties accruing before and after the patent was granted. The California Supreme Court held that Lear was estopped to deny the patent’s validity due to "one of the oldest doctrines in the field of patent law" which states that "so long as a licensee is operating under a license agreement he is estopped to deny the validity of his licensor’s patent in a suit for royalties under the agreement." The holding was based on a similar ruling made by the United States Supreme Court seventeen years earlier in Automatic Radio Mfg. Co. v. Hazeltine Research, 339 U.S. 827 (1950). The purpose of this note is twofold: first the history of the estoppel rule and the exceptions thereto will be traced; second the need and justification for some degree of pre-patent protection for the inventor will be discussed.

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