The trivia contest posted last week generated lots of interest.  Thanks for everyone who tried their hand at searching.  The contest goal was to find a seminal U.S. patent that teaches a fluid lens.  The question included the clues that the lens was patented prior to WWII, had no cited prior art, 14 independent claims, and no dependent claims. A small non-monetary prize was promised to the winner.

However — there will be no prize, because the winner is one of our fine USPTO Patent Examiners (Examiner-H) who was able to find U.S. Patent No. 2,062,468.  Ethical rules bar us from sending him a prize, and Examiner-H would prefer to remain anonymous.  Greg Aharonian would be proud.

About the patent: This "optical device" was patented by Charles H. Matz in 1936 teaches a "fluid lens." The strength of the lens can be altered by varying the curvature of the surface of the liquid.  Interestingly, Matz introduces the concept of varying the surface curvature (surface tension) by varying the voltage across the fluid lens.


  • Download The Patent
  • We’re making the contest a bi-annual event (every 6 months). Feel free to send me suggestions for contest. (patent law blogger — Dennis Crouch).
  • LINK: Paul Schwander from the EPO regularly provides a similar quiz in the IPR-helpdesk newsletter to help searchers build up their skills. FYI: IPR = Intellectual Property Rights.