LIDAR Detector Arrays with Dynamic SPAD Activation
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Solution Overview
Problem
Conventional LIDAR systems face challenges in efficiently managing power consumption and dynamic range in detector arrays, particularly with SPAD-based systems, which can be blinded by high ambient light and struggle with varying photon flux, leading to reduced detection capabilities and increased power usage.
Innovation Solution
Implementing a LIDAR system with multiple SPADs per pixel and a control circuit that dynamically adjusts the active detection area by selectively activating subsets of detector elements based on incident light conditions and distance ranges, allowing for varying sensitivity and power consumption, and incorporating polarization-selective detector elements to improve signal detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple SPADs are implemented per pixel to increase detection area, then the dynamic range is improved, but the power consumption increases
Solution Approach 1:
The detector array is segmented into multiple SPADs per pixel, allowing selective activation of subsets of detectors based on lighting conditions. This segmentation enables the system to adjust the effective detection area dynamically, resolving the contradiction between having large detection area for high dynamic range and consuming less power by activating only necessary detectors.
Solution Approach 2:
The patent implements dynamic control of detector activation states, where the number of active SPADs per pixel is adjusted in real-time based on ambient light intensity and distance range. This dynamic adjustment allows the system to optimize between detection capability and power consumption for different operating conditions.
2Adaptability or versatility
If all detector elements are activated to maximize detection area, then the dynamic range is improved, but the power consumption increases
Solution Approach 1:
Instead of activating all detector elements, the system activates only the necessary subset of SPADs based on current operating conditions. This partial action principle reduces power consumption while maintaining adequate detection capability for the given lighting and distance conditions.
Solution Approach 2:
The system changes the operational parameters of the detector array by dynamically adjusting the number of active detectors per pixel based on detected photon flux and ambient light conditions. This parameter adjustment optimizes the balance between detection performance and power consumption.
3Use of energy by moving object
If the detection area is reduced to lower power consumption, then the power consumption is reduced, but the dynamic range decreases
Solution Approach 1:
The system dynamically adjusts the detection area by varying the number of active SPADs per pixel based on real-time detection of photon flux and ambient light conditions. When light conditions are favorable, fewer detectors are activated; when conditions deteriorate, more detectors are activated to maintain dynamic range, thus resolving the contradiction between power consumption and detection capability.
4Measurement precision
If SPADs operate in Geiger mode for single photon detection, then the sensitivity is improved, but the device complexity increases
Solution Approach 1:
The system segments the detection function across multiple SPADs operating in Geiger mode, with each detector element independently capable of single-photon detection. This segmentation approach maintains high sensitivity while distributing the complexity across parallel simple detector units rather than requiring a single complex high-sensitivity detector.
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
This approach enhances the dynamic range and reduces power consumption of LIDAR systems by optimizing detector element activation, enabling effective operation in diverse lighting conditions and distance ranges while maintaining high sensitivity and reducing glare from polarized light sources.
Implementation Method 1
The initiating charge carrier can be photo-electrically generated by means of a single incident photon striking the high field region
Implementation Method 2
The high reverse bias voltage generates a sufficient magnitude of electric field such that a single charge carrier introduced into the depletion layer of the device can cause a self-sustaining avalanche via impact ionization
Implementation Method 3
At least one of the detector elements of the first and/or second subsets may include a polarizer thereon
Data Source
AI summary
A Light Detection And Ranging (LIDAR) detector circuit includes a plurality of detector pixels, where each or a respective detector pixel of the detector pixels includes a plurality of detector elements. At least one control circuit is configured to provide one or more detector control signals that selectively activate one or more of the detector elements of the respective detector pixel to define a first active detection area including a first subset of the detector elements for a first image acquisition, and a second active detection area including a second subset of the detector elements for a second image acquisition. Related devices and methods of operation are also discussed.