Johnsen-Rahbek effect

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The Johnsen-Rahbek effect is an electrostatic attraction between the surface of a weakly conductive material and a metal when an electrical voltage is applied . The strength of the attraction depends on the tension and the materials used.

The effect is named after the Danish engineers Frederik Alfred Johnsen (1887–1930) and Knud Rahbek (1891–1971). In their article published in 1923, they described how the effect can be used to build electrically controlled clutches . To do this, they stretched a metal band over a rotating cylinder made of porous material soaked with an electrolyte . The friction of the metal belt could be controlled by an electrical voltage between the belt and the cylinder . In this way, a limited number of loudspeakers and amplifiers have been built into telephone networks . Rahbek and Johnsen had already applied for a patent for this application of the effect in 1919. More recent studies deal with the application of the effect of holding semiconductor wafers in the manufacturing process.

A theoretical model for the effect empirically found by Johnsen and Rahbek was published by Albino Antinori as early as 1925. An extended model was set up by R. Atkinson. On the one hand, it takes into account imperfections of the surfaces, and on the other hand, the interface is modeled as a capacitor at which field emission occurs.

Individual evidence

  1. ^ A b c C. J. Fitch: Development of the Electrostatic Clutch . In: IBM Journal . tape 1 , no. 1 , 1957, pp. 49-56 ( portal.acm.org [PDF]).
  2. ↑ Knud Rahbek . In: The Danske Encyklopædi store . Retrieved January 12, 2010 (Danish).
  3. ^ Alfred Johnsen, Knud Rahbek: A physical phenomenon and its application to telegraphy, telephony etc. In: Journal of the Institution of Electrical Engineers . tape 61 , 1923, pp. 713-725 .
  4. ↑ Patent US1533757 : Apparatus for changing electrical variations to mechanical. Registered on March 10, 1919 , published on April 14, 1925 , inventor: K. Rahbek, FA Johnsen (names of inventors). ‌
  5. ↑ Shu Qin, Allen McTeer: Wafer dependence of Johnsen-Rahbek type electrostatic chuck for semiconductor processes . In: Journal of Applied Physics . tape 102 , no. 6 , 2007, p. 064901 , doi : 10.1063 / 1.2778633 .
  6. ↑ Gyu Il Shim, Hideo Sugai: Dechuck Operation of Coulomb Type and Johnsen-Rahbek Type of Electrostatic Chuck Used in Plasma Processing . In: Plasma and Fusion Research . tape 3 , no. 0 , 2008, p. 051 , doi : 10.1585 / pfr.3.051 ( jstage.jst.go.jp [PDF; 401 kB ]).
  7. ↑ Albino Antinori: About the origin of the Johnsen-Rahbek effect . In: Journal of Physics A . tape 34 , no. 1 , 1925, p. 705-714 , doi : 10.1007 / BF01328517 .
  8. ^ R. Atkinson: A simple theory of the Johnsen-Rahbek effect . In: Journal of Physics D: Applied Physics . tape 2 , no. 3 , 1969, p. 325-332 , doi : 10.1088 / 0022-3727 / 2/3/303 .