Air Speaker
A website devoted to massless loudspeakers  

plasma speaker chain

   

 

Air Speaker Patents

The following table lists all of the patents I have found to relate to the production of sound using electrical discharges of various forms.

I have included a brief note, my attempt to summarise the type of speaker the patent describes, and also a class description in which I have tried to categorise the particular invention.

If you wish to find the full detail of a particular patent I would recommend the espacenet website here http://ep.espacenet.com/ and search for the patent number, in the form US2793324 for example.

As you can see, there have been a good many patented designs for over a century - proving that air speakers are nothing new!

Listed in date order.

Country Patent No. Title Author Date Class Notes
GB 190604585 Improvements in and relating to… Hermanus 1906 A Arc microphone, piston against electrode
GB 191407202 Improved method of trans… Stille 1915 A Arc microphone (reverse of "singing arc")
GB 264811 Improvements relating to elec… General Electric 1927 B Point to plane corona discharge
GB 265958 Improvements relating to elec… General Electric 1928 C Points on a disc corona wind.
US 1685075 Intertransposition of sound … Lindenblad 1928 C Point to air/ground corona discharge. 189 patents!, Swedish
US 1758993 Sound reproducer Wolff 1930 C Many points corona discharge. Ref to above patent 1695075 wrong!
US 2768246 Electrical Transducer Klein S. 1956 B Ionovac, Also-GB756546, CH317527, DE1095883, FR1041790
GB 757358 Improvements in or relating to… Klein S. 1956 B Ionovac, Also-US2847516, GB757111, FR1041790, BE519086, FR67664E
US 2793324 Ionic triode speaker Halus, Holcomb 1957 B Corona discharge around a hole
GB 792312 Improvements in and relating to… Klein S. 1958 B Multi horn Ionovac
US 2949550 Electrokinetic apparatus Townsend Brown 1960 C Corona wind
US 3105124 Inertialess Transducer Torn 1963 B Dukane ionovac
FR 1427695 Appareil sonore électrohydro… Electrokinetics 1966 C Corona wind wire with backplate shapes
US 3018394 Generation and transmission … Townsend Brown 1967 C Corona wind
US 3476887 Ionic electroacoustic transducer Seligson, Lanier 1970 C Many points to blades corona wind (blades all vertical, points only one side)
GB 1274875 A system for imparting movem… Townsend Brown 1972 C Corona triode with vertical bars+wires.
DE 2115544 Koronaphon Walter 1972 B Circuit for a plasma loudspeaker (modulated supply?)
FR 2246151 none Doucet, Henri 1975 C Corona wind
JP 53141612 Grid controlled ionic wind loud… Kiyoshi 1978 B Corona triode, wires, single ended and push pull.
JP 53142218 Ionic Wind Loudspeaker… Kiyoshi 1978 B Corona triode, just single ended, points
JP 53137128 Ionic Wind Loudspeaker Kiyoshi 1978 B Corona triode, points, single ended and push pull.
GB 2023373 Plasma Loudspeaker Hill 1979 B

Plasmatronic, glow discharges in parallel. US4219705,JP54143225,JP2918300,FR2422314,DE2913804

EP 0017885 Corona-effect loudspeaker Klein S. 1980 B Magnat
EP 0017886 Corona-loudspeaker Klein S. 1980 B Magnat
US 4306120 Sound emitter Klein S. 1981 B Magnat/Ionovac
EP 0065911 Ionic electro-acoustic transducer Bondar 1982 C Plasmasonic, Also-US4460809,JP58001395,FR2506551,EP0065911
US 4464544 Corona-effect sound emitter Klein S. 1984 B Magnat
FR 2544951 Corona effect loudspeaker… Klein S. 1984 B Magnat
US 4482788 Transducer for the transformation Klein S. 1984 B Also EP0017886,SU1175352,JP55140400,FR245444, ES8100754
FR 2588710 Ionic electroacoustic transducer Deraedt 1987 C Push-pull corona wind
WO 8807785 Electrokinetic transducing met… Lee 1988 C Corona wind, Offset wires to thicker bars.
US 4789801 Electrokinetic transducing met… Lee 1988 C Corona wind, Offset wires to thicker aerodynamic bars.
EP 0370846 Electroacoustic Transducer Fourriere 1990 C Tolteque, Corona/Glow modulated by plates. JP2174398, FR2638930
JP 4027300 Method and device for arc sound… Eizo 1992 A Arc/flame nozzle, a TIG welder
US 5220246 Method and apparatus for tran… Ide, Hashimoto 1993 A Possible glow discharge (arc column), single point to plane. Based on DC TIG welder.
JP 6327099 Speaker utilizing DC corona dis… Masaaki 1994 B Point to plane corona discharge,+ push pull
GB 2312590 Corona Discharge Loudspeaker Howard 1997 C Corona wind wires with grids either side.
GB 2403372 Corona Discharge Loudspeaker Chambers 2004 C Corona wind
WO 127810 Electroststic Loudspeaker and ... Krichtapovitch 2007 C Kronos EPA application (not granted yet, company closed), here , corona wind

Classes of transducer :
A Arc discharge
B Glow discharge / Plasma
C Corona wind (ion cloud)