SPAD Array Segmentation for TOF Power Reduction
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Solution Overview
Problem
The existing detection devices using Time of Flight (TOF) technology face challenges with high data rates and accuracy due to the power consumption and data generation of Time Digital Converters (TDCs) in large pixel arrays, making it difficult to implement accurately and efficiently.
Innovation Solution
A detection device and method that utilize a pulse light source, a detector array with SPAD units, and a processing module to acquire excitation information in multiple windows, where the time widths of the windows are set based on probability thresholds or adaptive adjustments, allowing for statistical analysis and histogram construction to determine flight times without relying solely on TDCs for every event.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If TDCs are used for every pixel in large arrays to improve measurement precision, then timing resolution is improved, but power consumption and device complexity increase significantly
Solution Approach 1:
The patent divides the pixel array into multiple blocks, with only selected pixels in each block equipped with TDCs. This segmentation allows the system to maintain timing resolution for critical measurements while reducing the total number of TDCs needed, thereby lowering power consumption in large arrays.
Solution Approach 2:
Different pixels within the same block are treated differently - some pixels have TDCs while others use simpler timing methods. This local differentiation optimizes resource allocation by applying complex timing circuits only where necessary rather than uniformly across all pixels.
2Measurement precision
If TDCs are used for every pixel in large arrays to improve measurement precision, then timing resolution is improved, but device complexity increases
Solution Approach 1:
By segmenting the pixel array into blocks with selective TDC placement, the patent reduces the overall device complexity. Instead of requiring every pixel to have a full TDC, only representative pixels within each block need the complex timing circuitry.
Solution Approach 2:
Rather than equipping all pixels with TDCs and then trying to manage the complexity, the patent inverts the approach by using simpler timing methods for most pixels and adding TDC capability only to selected pixels where high precision is required.
3Measurement precision
If multiple TDCs are used per row of SPADs to improve measurement precision, then timing resolution is improved, but power consumption increases
Solution Approach 1:
The patent merges the timing functions of multiple pixels by using a single TDC for multiple pixels within a block. This consolidation allows the system to maintain measurement precision across multiple pixels while significantly reducing the total power consumption compared to having separate TDCs for each pixel.
Solution Approach 2:
A single TDC in each block serves multiple pixels, making it a multi-functional component. This universal TDC can handle timing measurements for any pixel within its block, reducing the overall number of TDCs needed and thereby lowering power consumption.
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 reduces computational intensity and power consumption while maintaining detection accuracy by using TDCs only when necessary, allowing for efficient photon counting and distance measurement in the detection device.
Implementation Method 1
A light pulse is continuously emitted to a target, a light returned from the target is received by a sensor
Implementation Method 2
The initial charge carrier may generate a photoelectric effect by a single incident photon striking a region of a high electric field
Implementation Method 3
A high reverse bias voltage may generate an electric field of sufficient magnitude, so that a single charge carrier introduced into a depletion layer of the device can cause a self-sustaining avalanche by collisional ionization
Data Source
AI summary
Provided are a detection apparatus and a detection method. The detection apparatus comprises: a pulse light source, which is configured to emit a pulse light signal; a detector array, which includes a plurality of pixel units, wherein at least some of the plurality of pixel units are operating units, and the operating units obtain excitation information in response to background light and/or signal light photons incident thereon during a plurality of windows; and a processing module, which acquires time range information according to the excitation information of the operating unit.