Rain sensor using low harmonic content signals
AssigneeValeo Auto-Electric Wischer und Motoren GmbH
InventorGerd Reime
Life of this patent
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Abstract
A rain sensor to detect humidity drops inside an area on a transparent window has at least one transmitting element to emit optical rays into the window and has at least one receiving element to receive at least one part of the emitted optical rays where the intensity of the optical rays received is dependent on the number of humidity drops in the area of the window observed by the rain sensor. So that interference from the rain sensor with radio broadcasts is effectively reduced and, if possible even completely prevented, the rain sensor has a generator to generate an electrical signal which has a lower harmonic content than square-wave signals, preferably a sine-wave electrical signal to power each transmitting element of the rain sensor.
Claims21
A rain sensor for detecting humidity drops within an area on a transparent window, the rain sensor comprising:
- at least one transmitting element for emitting optical rays into the window;
- at least one receiving element for receiving at least one part of the optical rays emitted, wherein the intensity of the optical rays received is dependent on the number of humidity drops in the area of the window observed by the rain sensor;
- and
- means for generating an electrical signal having a lower harmonic content than a square-wave signal, the generating means supplying the electrical signal to the at least one transmitting element of the rain sensor.
A method of operating a rain sensor to detect humidity drops within an area on a transparent window, the method comprising the steps of:
- emitting optical rays into the window using at least one transmitting element emits optical rays;
- receiving at least one part of the emitted optical rays using at least one receiving element, wherein the intensity of the received optical rays is dependent on the number of humidity drops in the area of the window observed by the rain sensor;
- and
- supplying power to the at least one transmitting element using an electrical signal having a lower harmonic content than a square-wave signal.
A rain sensor for a transparent window, comprising:
- a transmitting element for emitting optical rays into the window;
- a receiving element for receiving optical rays reflected from the window;
- means for generating an electrical signal and supplying the electrical signal to the transmitting element, the electrical signal having a lower harmonic content than a square-wave signal;
- and
- processing circuitry for receiving signals from the receiving element and for determining an amount of humidity drops on the window.
Dependencies are inferred from the claim text.