Binary Sensor Array with Spatially Varying Thresholds

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Solution Overview

Problem

Existing binary sensor systems face challenges in accurately estimating light intensity due to the assumption of fixed thresholds, which is not reflective of the actual variability in sensor thresholds, especially in sub-diffraction limit sensors with spatially varying activation values.

Innovation Solution

An array of sub-diffraction limit light sensors with adjustable light absorption activation thresholds, where a processor and memory configuration estimate light intensity based on electrical outputs using Bayesian inference or neural networks, accounting for variable thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If fixed threshold binary sensors are used, then device complexity is reduced, but measurement precision of light intensity deteriorates

Engineering Contradiction:
Improvesensor threshold configurationVSAvoidlight intensity estimation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes the threshold parameter from a fixed value to a spatially varying distribution across the sensor array. Each sensor element is assigned a unique threshold value drawn from a known probability distribution, enabling the system to encode additional information about light intensity through the pattern of activated sensors. This parameter transformation resolves the contradiction by maintaining simple binary sensor operation while improving measurement precision through threshold diversity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by assigning different threshold values to different spatial locations within the sensor array. Rather than using a uniform threshold across all sensors, each sensor element has a locally optimized threshold that contributes to the overall intensity estimation. This spatial variation in threshold quality enables more precise light intensity measurement while keeping individual sensor operations simple.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If spatially varying thresholds are implemented, then measurement precision of light intensity is improved, but device complexity increases

Engineering Contradiction:
Improvelight intensity estimation accuracyVSAvoidsensor threshold configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements self-service by using the natural fabrication variations in sensor thresholds rather than requiring precise manual calibration. The system accepts that thresholds will vary spatially due to manufacturing imperfections and leverages this variability as a feature rather than a defect. By using a known probability distribution to model these variations, the system automatically adapts to the specific sensor array configuration without requiring complex external calibration procedures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent employs feedback by using the known probability distribution of threshold values to inform the light intensity estimation process. The estimation algorithm incorporates knowledge of the threshold distribution to correctly interpret the pattern of activated sensors, transforming what would otherwise be ambiguous data into accurate intensity measurements. This feedback mechanism allows the system to achieve high measurement precision despite the complexity of spatially varying thresholds.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If binary sensor array with variable thresholds is used, then sensitivity across wide range of light intensities is enhanced, but manufacturing precision requirements are relaxed

Engineering Contradiction:
Improvesensitivity rangeVSAvoidsensor threshold uniformity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent converts the harmful effect of manufacturing precision variations into a beneficial feature. Instead of requiring tightly controlled, uniform threshold values across all sensors, the system embraces the natural variability introduced by relaxed manufacturing tolerances. By modeling this variability with a known probability distribution and incorporating it into the estimation algorithm, the system achieves enhanced sensitivity across a wide range of light intensities while accepting less stringent manufacturing precision requirements.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 enables accurate light intensity estimation even in arrays with spatially varying thresholds, improving imaging performance by leveraging variable threshold distributions and imperfections in fabrication, enhancing sensitivity across a wide range of light intensities.

Implementation Method 1

an array containing N sub-diffraction limit light sensors each having an associated light absorption activation threshold

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP2517459B1Intensity estimation using binary sensor array with spatially varying thresholds
Publication Date: 2021.02.17 NOKIA TECHNOLOGIES OY
  • EP2517459B1 patent drawingFigure 1A~1B
  • EP2517459B1 patent drawingFigure 2~3
  • EP2517459B1 patent drawingFigure 4

AI summary

An apparatus includes an array containing N sub-diffraction limit light sensors each having an associated light absorption activation threshold for switching from a reset state to an activated state, where the light absorption activation values lie within a range of values. The apparatus further includes a processor connected with a memory including computer program code, where the memory and computer program code are configured to, with the processor, cause the apparatus at least to perform estimating an intensity of light that illuminates the array based on electrical outputs of the array.