Optoelectronic angle of rotation sensor

A steering angle sensor for determining the absolute angle of rotation of a steering wheel of a motor vehicle, the sensor comprising:

• an encoder having a coding, the encoder being operable to be moved in a movement direction in response to rotational movement of a steering wheel, the coding having a plurality of adjacent portions each extending transversely to the movement direction of the encoder from one edge of the coding to the other edge of the coding and aligned across the coding in the movement direction of the encoder, each portion having an optical transmission value which sinusoidally changes at a respective frequency from one edge of the coding to the other edge of the coding, wherein the respective frequencies associated with the portions vary across the coding in the movement direction of the encoder such that the respective frequency associated with each portion of the coding is indicative of a respective angular position of the steering wheel;
• and
• a sensor array having a series of transducer elements for sensing the coding of the encoder, the sensor array arranged transversely to the movement direction of the encoder such that the transducer elements proportionally sense a respective portion of the coding at each angular position of the steering wheel, wherein the transducer elements generate an intensity signal indicative of the frequency associated with a sensed portion of the coding at an angular position of the steering wheel;
• wherein a frequency-related analysis of the intensity signal is performed to determine the angular position of the steering wheel from the frequency associated with the sensed coding portion.

An optoelectronic sensor for sensing angular position of an object, the sensor comprising:

• an encoder having a coding, the encoder being operable to be moved in a movement direction in response to rotational movement of an object, the coding having a plurality of adjacent portions each extending transversely to the movement direction of the encoder from one edge of the coding to the other edge of the coding and aligned across the coding in the movement direction of the encoder, each portion having an optical transmission value which sinusoidally changes at a respective frequency from one edge of the coding to the other edge of the coding, wherein the respective frequencies associated with the portions vary across the coding in the movement direction of the encoder such that the respective frequency associated with each portion of the coding corresponds to a respective angular position of the object;
• and
• a sensor array having a series of transducer elements for sensing the coding of the encoder, the sensor array arranged transversely to the movement direction of the encoder such that the transducer elements proportionally sense a respective portion of the coding at each angular position of the object, wherein the transducer elements generate an intensity signal indicative of the frequency associated with a sensed portion of the coding at an angular position of the object;
• wherein an analysis of the intensity signal is performed to determine the angular position of the object based on the frequency associated with the sensed coding portion.