Optical Distance Measuring Device and Method for Optical Distance Measurement

An apparatus comprising:

• a capacitive pixel sensor element subjected to a charge or discharge process in dependence on a measured quantity that can be detected at a pixel sensor element output;
• at least one buffer amplifier;
• first and second sample capacitances;
• first and second switches, via which the first or the second sample capacitance can be connected to the pixel sensor element output via the at least one buffer amplifier;
• a controller that is implemented to control the first and second switches such that the first switch is closed in a first time window and the second switch is closed in a second time window, wherein the first time window and the second time window temporally overlap such that, at the end of the first and second time windows, different voltage signals describing the charge or discharge process of the capacitive pixel sensor element are applied to the first and second sample capacitances.

A double sampling system comprising a plurality of apparatuses, the apparatuses comprising:

• a capacitive pixel sensor element subjected to a charge or discharge process in dependence on a measured quantity that can be detected at a pixel sensor element output;
• at least one buffer amplifier;
• first and second sample capacitances;
• first and second switches, via which the first or the second sample capacitance can be connected to the pixel sensor element output via the at least one buffer amplifier;
• a controller that is implemented to control the first and second switches such that the first switch is closed in a first time window and the second switch is closed in a second time window, wherein the first time window and the second time window temporally overlap such that, at the end of the first and second time windows, different voltage signals describing the charge or discharge process of the capacitive pixel sensor element are applied to the first and second sample capacitances;
• wherein the apparatuses are arranged in arrays, wherein an evaluator that can be coupled, with the help of a controller for controlling the arrays or the individual apparatuses via a select switch and a read line, to the voltage signals of the sample capacitances describing the charge or discharge process of the capacitive pixel sensor element is associated with every array or every single apparatus.

A method for optical distance measurement, comprising:

• emitting a radiation pulse with a pulsed radiation source implemented to transmit, in a temporally contiguous radiation pulse period, a radiation pulse with a pulse duration tp that is shorter than the radiation pulse period, and to transmit no radiation pulse in a temporally contiguous dark period;
• detecting different amounts of radiation with a detector that is implemented to capture reflections of the radiation pulse at an object surface and background radiation in two overlapping detection periods during the radiation pulse period and/or to capture background radiation in two overlapping detection periods during the dark period;
• and
• determining a signal depending on the distance to be measured based on the detected amounts of radiation.

A computer program comprising a program code for performing a method for optical distance measurement, the method comprising:

• emitting a radiation pulse with a pulsed radiation source implemented to transmit, in a temporally contiguous radiation pulse period, a radiation pulse with a pulse duration tp that is shorter than the radiation pulse period, and to transmit no radiation pulse in a temporally contiguous dark period;
• detecting different amounts of radiation with a detector that is implemented to capture reflections of the radiation pulse at an object surface and background radiation in two overlapping detection periods during the radiation pulse period and/or to capture background radiation in two overlapping detection periods during the dark period;
• and
• determining a signal depending on the distance to be measured based on the detected amounts of radiation,
• wherein the program code is performed on a computer, a microcontroller or a digital signal processor.