A history question about planar drivers

The Magnepan web site states that Magnepan founder Jim Winey developed the magnetic planar speaker and founded the company in 1969.

He had heard and liked electrostatic speakers, but as an engineer at 3M at the time, he thought there might be a way to drive the film magnetically instead of electrostaticly. He quit 3M, started Magnepan, and patented the product.

There is a link on the Magnepan website to a SoundStage! article on the company and discusses the product's history.

I believe that a speaker using the electrostatic approach came before the magnetic cone speaker. We are talking about the early years of the last century.

Yes, the design of electrostatic speakers is much older. There were experimental models in the Bell labs back in the 1920s.

Janszen tweeters were available in the early 1950s and Peter Walker came out with the Quad in the mid 1950s.