Proximity detector
AssigneeIdent Technology AG
InventorsPeter Fasshauer, Hans Schwaiger
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Abstract
A circuit for generating an indicative signal regarding the approach of an object to an observation area has a send electrode device, a generator circuit for supplying alternating voltage to the send electrode device, a receive electrode device which extends in or along the observation area, and an output circuit for generating an output signal correlating with the field at the receive electrode device. A compensation circuit is provided to add a compensation current i2 to a signal current i1 flowing from the receive electrode device.
Claims8
A circuit for generating a signal indicating the approach of an object to an observation area, the circuit comprising:
- a send electrode immediately adjacent the observation area;
- a generator for supplying alternating voltage to the send electrode to create adjacent the send electrode in the observation area an alternating electrical field;
- a receive electrode extending in or along the observation area for outputting an alternating electrical signal current i1 that varies as the object enters the area,
- a compensator for adding to the outputted signal current i1 of the receive electrode an alternating compensation signal current i2 having a phase offset by 180° to the signal current i1, and
- an output circuit for receiving the added signals i1 and i2 and generating an output signal correlating with the field at the receive electrode.
A method of generating a signal indicating the approach of an object to an observation area, the method comprising the steps of:
- feeding to a send electrode immediately juxtaposed with the observation area an alternating current to form in the area an alternating electrical field,
- detecting the field with a receive electrode extending in or along the observation area and outputting a signal current, and
- adding to the outputted signal current i1 of the receive electrode an alternating compensation signal current i2 having a phase offset by 180° to the signal current i1, and
- generating with an output circuit an output signal correlating with the field at the receive electrode.
Dependencies are inferred from the claim text.