초록 ▼

A sense electrode (12) is driven by a first oscillatory signal (26) and at least one control electrode (14) is driven by a second oscillatory signal (30). In first (38) and second (40) states (36), the second oscillatory signal (30) respectively has a first and second phase with respect to the first

A sense electrode (12) is driven by a first oscillatory signal (26) and at least one control electrode (14) is driven by a second oscillatory signal (30). In first (38) and second (40) states (36), the second oscillatory signal (30) respectively has a first and second phase with respect to the first oscillatory signal (26). The proximity of an electric-field-influencing media (20) to the proximity sensor (10) is responsive to the difference of third (50) and fourth (52) signals that are respectively measured when the second oscillatory signal (30) is in respective first (38) and second (40) states. The proximity sensor (10) is calibrated with a known capacitance operatively coupled to the sense electrode (12) with a plurality of switches (S1, S2) adapted so that the switches (S1, S2) have a relatively small effect on the capacitance of the sense electrode (12).

대표청구항 ▼

1. A proximity sensor for sensing an electric-field-influencing media within a region of space, comprising:a. a first electrode, wherein said first electrode is conductive; b. a first oscillatory signal operatively coupled to said first electrode; c. at least one second electrode, wherein said at le

1. A proximity sensor for sensing an electric-field-influencing media within a region of space, comprising:a. a first electrode, wherein said first electrode is conductive; b. a first oscillatory signal operatively coupled to said first electrode; c. at least one second electrode, wherein said at least one second electrode is conductive and said at least one second electrode is separated from said first electrode; d. a second oscillatory signal operatively coupled to said at least one second electrode, wherein said second oscillatory signal comprises a state, said state is selected from a first state and a second state, when in a first state said second oscillatory signal has a first phase relative to said first oscillatory signal, when in a second state said second oscillatory signal has a second phase relative to said first oscillatory signal; e. a means for controlling said state of said second oscillatory signal; f. a means for measuring a third signal from said first electrode when said second oscillatory signal is in said first state; g. a means for measuring a fourth signal from said first electrode when said second oscillatory signal is in said second state; h. a means for forming a difference of said third and fourth signals; and i. a means for generating a measure of proximity of an object to said proximity sensor responsive to said difference.