Electrode-Array Photodetector for Gapless LiDAR Pixel Detection
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Solution Overview
Problem
LiDAR systems face challenges in maintaining spatial resolution due to gaps between photodiodes in photodetector arrays, leading to photon loss and increased noise floor, while eliminating these gaps results in loss of spatial resolution and increased parasitic capacitance.
Innovation Solution
A single photodetector with an array of electrodes is used, where each electrode corresponds to a different pixel position, and a processor detects the pixel position by identifying the electrode producing the largest signal, aided by operational amplifiers and analog-to-digital converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If gaps are eliminated by using one large photodiode detector instead of an array of small photodiode detectors, then photon energy loss is eliminated, but spatial resolution is lost and noise floor increases significantly
Solution Approach 1:
The single photodiode detector is segmented into multiple electrode regions, where each electrode corresponds to a specific spatial position or angular direction. This segmentation allows the detector to maintain continuous coverage (no gaps) while preserving spatial resolution by assigning different regions to different measurement channels.
Solution Approach 2:
Multiple photodiode elements are merged into a single continuous photodiode detector with multiple electrodes. This combining eliminates the gaps between individual photodiodes, ensuring complete photon collection, while the electrode segmentation maintains the ability to distinguish spatial positions through signal processing.
2Loss of energy
If gaps are eliminated by using one large photodiode detector, then photon energy loss is eliminated, but noise floor increases significantly due to larger parasitic capacitance
Solution Approach 1:
The large photodiode is segmented into multiple electrode regions, each with its own readout circuit. This segmentation divides the total parasitic capacitance into smaller portions, reducing the noise contribution from each electrode while maintaining complete coverage for photon collection.
3Measurement precision
If an array of photodiodes is used, then spatial resolution is maintained, but gaps between photodiodes cause photon loss
Solution Approach 1:
Multiple photodiode elements are merged into a single continuous photodiode detector with multiple electrodes. This eliminates the physical gaps between individual photodiodes, ensuring that photons from all angular directions are collected without loss, while the electrode segmentation preserves spatial resolution.
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 allows for spatial resolution without gaps, ensuring photon collection from arbitrary angles and reducing noise, thereby enhancing LiDAR system performance.
Implementation Method 1
A photodetector sufficiently large to receive an entire designed field of view of the LiDAR system... each electrode corresponding to a different pixel position
Data Source
AI summary
A photodetector is made sufficiently large to receive an entire designed field of view (e.g., for a LiDAR system). At least one lens is mounted to direct reflected laser beams to the photodetector. A plurality of electrodes (e.g., 16, 32 or 64) are coupled to the photodetector, each electrode corresponding to a different pixel position. A processor is coupled to the plurality of electrodes and the processor is configured to detect a pixel position of a reflected laser beam by detecting which electrode produces the largest digital signal.