Hybrid TOF Sensor with SPAD Array for Dynamic Range
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Single-photon avalanche diodes (SPADs) used in time-of-flight (TOF) measurement systems face challenges in achieving high resolution and dynamic range due to high power consumption, making it difficult to effectively measure time-of-flight over a wide detection range in both direct and indirect TOF methods.
Innovation Solution
A hybrid TOF sensor system utilizing a single-photon avalanche diode with a configuration that includes a detector array, digital control unit, counter array, and logical control unit, capable of operating in both direct and indirect TOF modes, which divides the SPAD input pulse into in-phase and out-of-phase counters and uses a global phase-locked-loop for high-frequency clocking, allowing for high dynamic range measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If single-photon avalanche diodes are used for time-of-flight measurement, then time-of-flight resolution is improved, but power consumption increases
Solution Approach 1:
The system dynamically switches between direct TOF mode and indirect TOF mode based on the detection range requirements. In direct TOF mode, high-resolution timing is used for short-range measurements, while in indirect TOF mode, phase-based measurement is used for long-range measurements. This dynamic operation mode allows the system to achieve high time-of-flight resolution when needed while consuming less power by using the more power-efficient indirect method for other measurements.
2Measurement precision
If direct TOF method is used, then time-of-flight measurement accuracy is improved, but detection range is limited
Solution Approach 1:
The TOF sensor system is designed to perform both direct time-of-flight measurement and indirect time-of-flight measurement functions within a single device. The system includes both direct TOF circuitry for high-accuracy short-range measurement and indirect TOF circuitry for extended-range measurement, making the system universally applicable across multiple detection range requirements without needing separate dedicated systems.
3Adaptability or versatility
If indirect TOF method is used, then detection range is extended, but measurement accuracy decreases
Solution Approach 1:
The system dynamically selects between direct and indirect TOF measurement modes based on the required measurement accuracy and detection range. For measurements requiring high precision, the system switches to direct TOF mode. For measurements requiring extended detection range where slightly lower precision is acceptable, the system uses indirect TOF mode. This dynamic adaptation allows the system to optimize the trade-off between accuracy and detection range for each specific measurement scenario.
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 system achieves improved dynamic range and efficient time-of-flight measurements by enabling operation in both DTOF and ITOF modes, allowing for precise distance determination over a wide range with reduced power consumption.
Implementation Method 1
Single-photon avalanche diodes (SPADs) are detectors capable of capturing individual photons with very high time-of-flight resolution
Data Source
AI summary
Disclosed is a time-of-flight sensing apparatus and method. In one embodiment, a system for time-of-flight (TOF) sensing, comprising: a detector array comprising a plurality of single-photon avalanche detectors (SPADs); and a control circuit comprising at least two digital control arrays coupled to the detector array, a counter array coupled to the at least two digital control arrays, and a logical control unit coupled to the counter array and the at least two digital control arrays, wherein the detector array is configured to receive at least one reflected light pulse from a target, wherein a first digital control array, the counter array, and the logical control unit of the control circuit are configured to receive at least one avalanche pulses from each of the plurality of SPADs to determine a first distance between the detector array and the target in a first TOF mode, and wherein a second digital control array, the counter array, and the logical control unit of the control circuit are configured to receive the at least one avalanche pulse from the each of the plurality of SPADs to determine a second distance between the detector array and the target in a second TOF mode.