Segmented Photodetector Array for LIDAR Eye Safety and Range
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Solution Overview
Problem
Current LIDAR systems face limitations in maximum illumination power due to eye safety regulations, which restrict their ability to reliably detect far-away objects under varying environmental conditions.
Innovation Solution
A LIDAR system with a processor-controlled light source and deflector that adjusts illumination based on reflection signals from both visible and supplementary sensors to prevent excessive energy density within a safe exposure limit, enabling detection of objects within and outside the primary field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the illumination power of LIDAR systems is increased to detect far-away objects, then the detection range is improved, but the eye safety regulation compliance deteriorates due to excessive energy density
Solution Approach 1:
The patent segments the photodetector array into multiple regions with different performance characteristics. Specifically, it divides the detection area into a first region with first photodetectors having first performance characteristics and a second region with second photodetectors having second performance characteristics. This segmentation allows the system to process reflected light from different spatial zones differently, enabling extended detection range while maintaining eye safety compliance by appropriately weighting signals from different regions.
Solution Approach 2:
The patent applies local quality by assigning different performance characteristics to different regions of the photodetector array. The first photodetectors in the first region have different characteristics (e.g., sensitivity, response time) compared to the second photodetectors in the second region. This allows the system to optimize detection for specific zones - potentially using higher sensitivity in regions corresponding to farther distances while maintaining overall eye safety compliance.
2Object-affected harmful factors
If the illumination power is limited to comply with eye safety regulations, then the eye safety compliance is improved, but the detection reliability of far-away objects deteriorates
Solution Approach 1:
The patent implements dynamic operation by allowing the LIDAR system to adjust its detection parameters based on real-time conditions. The processor controls the light source and light deflector dynamically, and the photodetector array with regions of different performance characteristics enables adaptive signal processing. This dynamic approach allows the system to maintain eye safety compliance while optimizing detection reliability for far-away objects by adjusting sensitivity and integration parameters based on detected signal strength and distance.
Solution Approach 2:
The patent incorporates feedback mechanisms where the processor receives detection signals from the photodetector array and uses this information to adjust system operation. The feedback loop allows the system to monitor detection quality and adjust illumination parameters, photodetector activation, and signal processing to maintain optimal detection reliability while staying within eye safety limits. The system can identify when far-away objects are detected and adjust parameters to improve reliability without exceeding safety thresholds.
3Device complexity
If a single photodetector type is used in the LIDAR system, then the device complexity is reduced, but the detection capability for objects at varying distances deteriorates
Solution Approach 1:
The patent segments the photodetector array into multiple regions with different performance characteristics to enhance detection capability for objects at varying distances. By dividing the detection area into distinct regions with specialized photodetectors, the system can optimize for both near and far object detection without requiring a completely separate detector for each distance range.
Solution Approach 2:
The patent creates a universal photodetector array where different regions serve multiple functions. The first and second photodetector regions can both detect objects at various distances, but their different performance characteristics make them suitable for different detection scenarios. This multi-functional design allows a single array to handle diverse detection requirements that would otherwise require multiple specialized detectors.
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
Enhances the detection range and reliability of LIDAR systems by ensuring compliance with eye safety regulations while improving the detection of objects beyond the direct field of view.
Implementation Method 1
A photodetection sensor having a plurality of performance characteristics may comprise a semiconductor photodiode chip having a detection area and a photodetector array located within the detection area
Implementation Method 2
A light detection and ranging system, (LIDAR a/k/a LADAR) is an example of technology that can work well in differing conditions, by measuring distances to objects by illuminating objects with light and measuring the reflected pulses with a sensor
Data Source
Figure 1A
Figure 1B~1C
Figure 2A
AI summary
A photodetection sensor having a plurality of performance characteristics includes a semiconductor photodiode chip having a detection area and a photodetector array located within the detection area. The photodetector array may comprise a first photodetector having a first performance characteristic, wherein the first photodetector is configured to generate a first detection signal based on light transmitted toward a plurality of target objects and reflected from at least a first object of the plurality of target objects to the first photodetector, and wherein the first detection signal is indicative of a time-of-flight of the light transmitted toward the plurality of target objects and reflected from the first object of the plurality of target objects to the first photodetector; and a second photodetector having a second performance characteristic different from the first performance characteristic, wherein the second photodetector is configured to generate a second detection signal based on the light transmitted toward the plurality of target objects and reflected from at least a second object of the plurality of target objects to the second photodetector; and wherein the second detection signal is indicative of a presence of at least one of the plurality of target objects which is undetectable from the first detection signal.