Optoelectronic sensor and method for measuring a distance

A method for measuring a distance of an object (18) in accordance with a time of flight principle, the method comprising the steps of

• transmitting a light signal (14);
• receiving the light signal (22) after reflection or remission by the object (18) in a light receiver (22) having a first plurality of pixel elements (24, 24a) each configured as an avalanche photo diode element biased with a bias voltage greater than a breakthrough voltage and thus operated in a Geiger mode in order to trigger an avalanche event upon light reception, and
• determining a time of flight between transmission and reception of a light signal (14, 22) by means of a second plurality of time of flight measuring units (34a) connected to pixel elements (24a), the second plurality being less than the first plurality,
• connecting only a selected portion of the pixel elements (24a) to time of flight measuring units (34a) in a one-to-one fashion, so that only some of the pixel elements (24a) are used for time of flight measurement,
• and selecting pixel elements (24a) to be connected based on an intensity measurement, thus excluding pixel elements actually only contributing ambient light or dark count events from the distance measurement.

An optoelectronic sensor (10) for measuring a distance of an object (18) in accordance with a time of flight principle, the sensor (10) comprising

• a light transmitter (12) for transmitting a light signal (14),
• a light receiver (22) for receiving the light signal (20) after reflection or remission by the object (18), the light receiver (22) having a first plurality of pixel elements (24, 24a) each configured as an avalanche photo diode element biased with a bias voltage greater than a breakthrough voltage and thus operated in a Geiger mode in order to trigger an avalanche event upon light reception
• and a distance measuring unit (34) having a second plurality of time of flight measuring units (34a) connected to pixel elements (24a) for determining a time of flight between transmission and reception of a light signal, the second plurality being less than the first plurality,
• switching means (32, 32a) for connecting only a selected portion of the pixel elements (24a) to time of flight measuring units (34a) in a one-to-one fashion, so that only some of the pixel elements (24a) are used for time of flight measurement,
• and a pixel selection unit (28, 30) for determining pixel elements (24a) to be connected by the switching means (32, 32a) based on an intensity measurement, thus excluding pixel elements actually only contributing ambient light or dark count events from the distance measurement,
• wherein the switching means (32) comprise a matrix of programmable interconnections (32a),
• and wherein the pixel selection unit (28) comprises a plurality of counters (28a), each counter (28a) being connected with at least one pixel element (24) for counting avalanche events of the connected pixel elements (24).