Capacitive proximity sensor and mobile device
AssigneeSemtech Corporation
InventorsChaouki Rouaissia, Sebastien Grisot
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Abstract
A proximity sensor for detecting proximity of a body portion in a first region while avoiding unwanted detection of a body portion in a second region, based on the capacities seen by a plurality of electrodes. An application of the inventive detector to a mobile phone, whereby the display is switched off, or various energy saving measure are taken, when the proximity sensor determines directional proximity with a body part, indicating that the user has brought the phone to the ear for placing a call.
Claims13
A proximity sensor for detecting proximity of a body portion in a first region while avoiding unwanted detection of a body portion in a second region, comprising:
- a plurality of capacitive electrodes for detecting said body portion in respective detection regions;
- an electronic circuit receiving signals from said capacitive electrodes, arranged for producing a directional proximity detection signal when said body portion is in said first region and not in said second region, based on the capacities seen by said capacitive electrodes,
- wherein said plurality at capacitive electrodes include;
- an internal capacitive electrode for detecting said body portion in the first region;
- an external capacitive electrode for detecting said body portion in the second region;
- a conductive shield for limiting the sensibility of the internal electrode to body portions in the second region and for limiting the sensibility of the external electrode to body portions in the first region,
- and the electronic circuit is arranged for producing a detection signal when a body portion is in the first region but not when a body portion is in the second region.
Dependencies are inferred from the claim text.