The Beginnings of the Nobel Institution - The Science Prizes, 1901 - 1915
[Elisabeth Crawford, Cambridge University Press ISBN 0 521 34747 5]

Page 160:

"The most important restriction put on the term 'invention' concerned patented work, the rewarding of which had caused hesitation when the statutes where drawn up.
Since no provision barring such work from the prizes had been included in the statutes, the physics committee took up the matter in 1901. It decided that a formal change was unnecessary, given members' agreement that, as a rule, 'patented inventions should not be taken into consideration'. Proposals to reward patented work were not rejected out of hand, but in general the positive application of the term invention required - in addition to the considerations of its 'benefit for mankind', to be discussed below - that the candidate be deserving of the prize because he had not derived any financial benefits from the invention. Few candidates met this requirement, since if an invention had been successful, it had normally been patented and hence brought some wealth to its author"

Page 262, notes:

19. Protokoll, NK, Fysik, February 2, 1901. In the negotiations over the statutes, Sohlman had proposed that patented inventions be the object of prize awards only if their authors relinquish patent rights. In the Large Nobel Committee, an equal number of votes were cast for and against this provision, and it was not included in the statutes (protokoll hållna vid sammanträden för överläggning om Alfred Nobels testamente, pp. 29-30)