Pixel Output Processing Circuit for Laser Range Finding
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Solution Overview
Problem
Conventional focal plane arrays (FPAs) with laser range finding (LRF) capabilities have components like high bandwidth amplifiers and comparators integrated within the pixels, which limits the flexibility and efficiency of pixel output processing for determining time-of-flight of laser pulses.
Innovation Solution
A pixel output processing circuit external to the pixels is introduced, featuring a common net and detection circuit that includes amplifying transistors, comparators, and synchronization circuits to process high-frequency analog signals from LRF pixels, allowing for external processing of time-of-arrival data with reduced component count within the pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high bandwidth amplifiers and comparators are integrated within the pixels, then LRF functionality is achieved, but device complexity and pixel area increase
Solution Approach 1:
The patent extracts the high bandwidth amplifier and comparator from the pixel structure and relocates them to external readout circuitry. The pixel now only contains a simplified photodetector and timing circuit, while the complex signal processing components operate externally, reducing pixel complexity while maintaining LRF functionality.
Solution Approach 2:
The system is segmented into distinct functional modules: the pixel array for photon detection, external amplification stages for signal boosting, and separate comparison/timing circuits for TOA measurement. This segmentation allows each component to be optimized independently and reduces the complexity burden on individual pixels.
2Productivity
If high bandwidth amplifiers and comparators are integrated within the pixels, then signal processing capability is improved, but manufacturing complexity increases
Solution Approach 1:
By extracting the complex amplifier and comparator circuits from the pixel fabrication process and implementing them as separate external components, the patent simplifies pixel manufacturing while maintaining high signal processing capability through dedicated external processing stages.
3Adaptability or versatility
If external processing circuit is used, then pixel flexibility is enhanced, but signal processing speed may be reduced
Solution Approach 1:
The external processing circuit is designed with pre-configured high bandwidth amplifiers and comparators that are ready to immediately process signals from any pixel. This preliminary preparation of processing resources maintains fast response times while allowing flexible configuration of which pixels are actively processed and how their signals are handled.
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 solution enables precise and efficient determination of time-of-flight with a temporal resolution of less than 10 ns, minimizing the number of components within the pixels and enhancing the flexibility of LRF operations in FPAs.
Implementation Method 1
A focal plane array (FPA) can include an array of pixels that receives laser pulses reflected from a target
Implementation Method 2
the comparator compares a voltage associated with the common net to a voltage associated with a reference net
Implementation Method 3
The common net is connected to a amplifying transistor of each of the LRF pixels for receiving analog signals output from the respective LRF pixels
Data Source
AI summary
A pixel output processing circuit of a focal plane array (FPA) having a plurality of laser range finding pixels (LRF) is provided. The respective LRF pixels output a high frequency analog signal in response to sensing a reflected laser pulse. The pixel output processing circuit includes a common net and a detection circuit. The common net is connected to a amplifying transistor of each of the LRF pixels for receiving analog signals output from the respective LRF pixels. The detection circuit is coupled to the common net and outputs a pulse flag in response to detecting that a high frequency analog signal has been received by the common net.