| US 7,466,146 B2 | ||
| Frozen material detection using electric field sensor | ||
| Bradley Clayton Stewart, Phoenix, Ariz. (US); Sergio Garcia de Alba Garcin, Jalisco (Mexico); Rogelio Reyna Garcia, Jalisco (Mexico); Gabriel Sanchez Barba, Jalisco (Mexico); and David L. Wilson, Muskego, Wis. (US) | ||
| Assigned to Freescale Semiconductor, Inc., Austin, Tex. (US) | ||
| Filed on Mar. 10, 2006, as Appl. No. 11/373,071. | ||
| Prior Publication US 2007/0209446 A1, Sep. 13, 2007 | ||
| Int. Cl. G01R 27/26 (2006.01); G01R 29/12 (2006.01); F25D 21/02 (2006.01); G08B 19/02 (2006.01); G08B 21/00 (2006.01) | ||
| U.S. Cl. 324—663 [324/671; 324/686; 324/688; 324/457; 62/128; 340/580; 340/962] | 18 Claims |
| 1. An apparatus comprising:
a first electrode;
a second electrode located at a distance from the first electrode, the second electrode forming a capacitive element with
the first electrode, wherein a gap is present between the first and second electrodes, wherein each of the first electrode
and second electrode partially surrounds a member subject to accumulation of frozen material, such that the gap is formed
between edges of the first and second electrodes along lateral sides of the member;
an electric field sensor having an electrode terminal coupled to the first electrode and providing an electric field output
value representative of an amount of frozen material located in the gap between the first and second electrodes;
a first insulating layer around the member, between the member and the first electrode and between the member and the second
electrode; and
a conductive layer around the member, between the member and the first insulator, wherein a shield output of the electric
field sensor is coupled to the conductive layer.
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