(12) United States Patent ao) Patent No.: Us 7,603,917 B2
Graham et al. (45) Date of Patent: Oct. 20,2009
PCT Pub. Date: Feb. 16, 2006
(65) Prior Publication Data
US 2008/0264183 Al Oct. 30, 2008
(30) Foreign Application Priority Data
Aug. 9, 2004 (GB) 0417683.0
(51) Int. CI.
G01D 7/00 (2006.01)
(52) U.S. CI 73/862.043
(58) Field of Classification Search
73/862.041-862.046 See application file for complete search history.
(56) References Cited
U.S. PATENT DOCUMENTS
4,094,192 A 6/1978 Watson etal.
4,320,392 A 3/1982 Giovinazzo et al.
4,555,960 A 12/1985 King
4,811,608 A 3/1989 Hilton
A sensor (100) for detecting input force and/or torque with six degrees of freedom for use as a computer input device is provided. The sensor has a technically simple detection mechanism which obviates the need for complex and fragile securing components. A user-manipulable core (106) is enclosed in a casing (109). Electrodes (114) in the casing (109) are separated from the core (106) by a layer of elastically deformable conductive polymer (108). Electric current flows between the core (106) and the electrodes (114). The polymer (108) has variable resistivity depending on the stress it experiences. Manipulation of the core (106) causes deformation of the polymer (108); the type of deformation, and hence the type of force/torque applied to core (106), is determinable from the currents flowing through the electrodes (114).
10 Claims, 13 Drawing Sheets