Patent attributes
An optical sensor for a touch-sensitive push button of a control mechanism for an electronic household appliance has a transmitter, which emits electromagnetic radiation, and a receiver, which receives reflected electromagnetic radiation. A cover is at least partly transparent to the electromagnetic radiation and the transmitter and the receiver are arranged behind the cover. A radiation guide mechanism, for example a diaphragm frame, is provided between the transmitter and the receiver, on the one hand, and the cover, on the other hand, for guiding the radiation emitted from the transmitter towards the cover and to guide the reflected radiation penetrating the cover to the receiver. The diaphragm frame broadens the emission characteristic of the transmitter outward from the cover and/or the reception characteristic of the receiver inward into the cover. Additionally or alternatively, the emission characteristic outward from the cover is inclined in the direction of the reception characteristic of the receiver into the cover and/or the reception characteristic of the receiver into the cover is inclined in the direction of the emission characteristic of the transmitter out from the cover. This moves the range of intersection between emission and reception characteristic closer to the cover, so that the signal-to-noise ratio of the optical sensor is reduced.
