SPAD Photon Detection Rate Controller for TOF Distance Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In Time of Flight (TOF) range sensors, the accuracy of distance detection is compromised due to distortion in histograms caused by high light intensity, leading to incorrect distance measurements, especially with objects of high reflectivity or at short distances.
Innovation Solution
A light detection device with a SPAD photon detection rate controller that adjusts the light emission amount and voltage of the light-emitting unit, and the number of SPADs in the arrays, to maintain an optimal photon detection rate within a specific range, preventing saturation and ensuring accurate distance calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light emission amount is increased to improve the photon detection rate, then the detection sensitivity is enhanced, but the histogram distortion occurs due to saturation
Solution Approach 1:
The patent implements a feedback control mechanism where the control unit monitors the photon detection rate and dynamically adjusts the light emission amount. When the photon detection rate exceeds a predetermined threshold, the control unit reduces the light emission amount to prevent saturation and histogram distortion, thereby maintaining reliable distance measurements while optimizing detection sensitivity.
Solution Approach 2:
The patent dynamically changes the light emission parameter (emission amount) based on the detected photon detection rate. By adjusting this parameter in real-time, the system maintains the photon detection rate within an optimal range, preventing both under-detection and saturation conditions that would compromise measurement accuracy.
2Measurement precision
If the number of SPADs is increased to enhance the photon detection capability, then the detection sensitivity is improved, but the device complexity increases
Solution Approach 1:
The patent employs only the necessary number of SPADs required to achieve the target photon detection rate, avoiding the deployment of excessive SPADs that would increase device complexity. The control unit optimizes the utilization of SPADs by dynamically adjusting the light emission amount, ensuring that the existing SPAD array operates at optimal capacity without requiring expansion.
3Measurement precision
If the light emission amount is continuously adjusted to maintain optimal photon detection rate, then the measurement accuracy is maintained, but the control complexity increases
Solution Approach 1:
The patent implements a feedback control mechanism where the control unit monitors the photon detection rate and dynamically adjusts the light emission amount. When the photon detection rate exceeds a predetermined threshold, the control unit reduces the light emission amount to prevent saturation and histogram distortion, thereby maintaining reliable distance measurements while optimizing detection sensitivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances the accuracy of distance detection by controlling the light emission and SPAD operation, reducing distortion and maintaining precise measurements even with high reflectivity or short-distance objects.
Implementation Method 1
the detection of the single photon is achieved by reverse biasing the avalanche photodiode with a voltage greater than a breakdown voltage VBD... When a photon is incident and causes avalanche amplification
Data Source
AI summary
A first SPAD array on which at least one first light beam that is at least one pulse light beam is incident and which is operated in Geiger mode, a second SPAD array on which at least one second light beam resulting from the at least one first light beam reflected by a detection object is incident and which is operated in Geiger mode, a voltage generation unit that applies a reverse bias voltage to the first SPAD array and the second SPAD array, and a SPAD photon detection rate controller that adjusts and controls a SPAD photon detection rate in accordance with a first photon detection rate indicating a rate of the number of at least one pulse signal output by the second SPAD array upon incidence of the at least one second light beam relative to the number of the at least one pulse light beam are included.