The headphone world has recently seen an influx of Planar-Magnetic Headphones, even though the techonology has been around for many years. 

Planar Magnetic Headphones are often called Orthodynamic, a technical term advanced / popularized by Yamaha in 1976  to describe their line of headphones at the time using a driver type known generically as isodynamicplanar-magnetic, or magnetostatic incorporating characteristics of both dynamic and electrostatic driver design.