Distance measurement device

Patent metadata

Field	Value
Publication number	US-2016124091-A1
Application number	US-201414889945-A
Country	US
Kind code	A1
Filing date	Apr 4, 2014
Priority date	May 10, 2013
Publication date	May 5, 2016
Grant date	—

Abstract

A distance measurement device according to one aspect of the present invention includes a photoelectric conversion device which includes a light receiving unit, a charge storage unit, a charge discharge unit, and a gate electrode, a controller which controls an irradiation timing of pulse light having a pulse width which is sufficiently shorter than response time of the light receiving unit to an object and performs control to generate control pulse voltages having at least two kinds of phases based on the irradiation timing and to apply it to the gate electrode, a charge reading unit which reads a first and second charges stored in the charge storage unit according to the applications of the respective control pulse voltages having two kinds of phases as a first and second electrical signals, and a calculation unit which calculates a distance to the object based on the first and second electrical signals.

First claim

1 . A distance measurement device comprising:
a photoelectric conversion device configured to include a light receiving unit for converting incident light into a charge, a charge storage unit for storing the charge, a charge discharge unit for discharging the charge, and a gate electrode for controlling transfer of the charge from the light receiving unit to the charge storage unit and transfer of the charge from the light receiving unit to the charge discharge unit; a controller configured to control an irradiation timing of pulse light having a pulse width which is sufficiently shorter than response time of the light receiving unit to an object and perform control to generate control pulse voltages having at least two kinds of phases based on the irradiation timing and to apply it to the gate electrode; a charge reading unit configured to read a first and second charges stored in the charge storage unit according to the applications of the respective control pulse voltages having two kinds of phases as a first and second electrical signals; and a calculation unit configured to calculate a distance to the object based on the first and second electrical signals.

2 . The distance measurement device according to claim 1 , wherein
the calculation unit calculates the distance based on a ratio between the first and second electrical signals by approximating impulse response characteristics of the light receiving unit.

3 . The distance measurement device according to claim 2 , wherein
the calculation unit approximates the impulse response characteristics of the light receiving unit by a linear function or a quadratic function.

4 . The distance measurement device according to claim 1 , wherein
the controller performs control to generate more control pulse voltages having phases different from the two kinds of phases, the charge reading unit further reads a third charge stored in the charge storage unit according to the application of the control pulse as a third electrical signal, and the calculation unit calculates the distance to the object based on the first and second electrical signals corrected by the third electrical signal.

5 . The distance measurement device according to claim 1 , wherein
the photoelectric conversion device includes a plurality of the light receiving units arranged in the photoelectric conversion device.

6 . The distance measurement device according to claim 1 , wherein
the photoelectric conversion device further includes a buffer circuit, and the control pulse voltage is applied to the gate electrode via the buffer circuit.

Assignees

• Univ Shizuoka Nat Univ Corp

Inventors

• Kawahito Shoji
• Yasutomi Keita

Classifications

• G01S7/4865

  Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak (peak detection in noise, signal conditioning G01S7/487) · CPC title

• G01S7/4863

  Detector arrays, e.g. charge-transfer gates · CPC title

• G01S17/10

  using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) · CPC title

• G01S17/894

  Three-dimensional [3D] imaging with simultaneous measurement of time-of-flight at a two-dimensional [2D] array of receiver pixels, e.g. time-of-flight cameras or flash lidar · CPC title

• G01S17/26 Primary

  wherein the transmitted pulses use a frequency-modulated or phase-modulated carrier wave, e.g. for pulse compression of received signals · CPC title