Bound-Mode Sensor Array for CMOS Spectral and Angular Sensing
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Solution Overview
Problem
Current smart lighting technologies face challenges in achieving high spectral and angular sensitivity with scalable and manufacturable processes, particularly in the visible spectrum, due to limitations in existing color cameras and plasmonic structures, which restrict their ability to adapt to varying lighting conditions and LED aging.
Innovation Solution
The development of a 2-D sensor array using grating coupling to bound modes propagating on a metal surface or waveguide modes confined by a dielectric stack, integrated onto a silicon surface, allowing for both spectral and angular sensitivity with a CMOS-compatible p-n junction technology that accommodates the short penetration depth of blue photons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate fabrication steps are used for each wavelength/angle setting, then manufacturing precision can be improved, but device complexity and ease of manufacture deteriorate
Solution Approach 1:
The patent combines multiple wavelength and angle settings into a single integrated sensor array structure. Different spectral bands (blue, green, red) and angular ranges are simultaneously fabricated using one unified process, eliminating the need for separate fabrication steps for each setting while maintaining precise wavelength and angle selectivity through the sensor design itself
2Ease of manufacture
If silicon-based detectors are used, then ease of manufacture is improved, but spectral resolution deteriorates due to varying absorption across the visible spectrum
Solution Approach 1:
The patent applies local quality by using silicon-based detectors with wavelength-selective filtering structures. Each pixel in the sensor array is equipped with specific filters (e.g., blue-pass, green-pass, red-pass filters) that are locally applied to compensate for silicon's varying absorption characteristics across the visible spectrum, enabling precise spectral resolution while maintaining CMOS manufacturing compatibility
3Measurement precision
If spectral resolution is improved to ≲30 nm, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the sensor array into multiple pixel types, each dedicated to specific spectral bands (blue, green, red regions). This segmentation allows each pixel group to be optimized for its specific wavelength range with appropriate filtering, achieving high spectral resolution of ≲30 nm while keeping the overall device structure manageable through functional division
4Measurement precision
If angular resolution is improved to 100 mrad, then measurement precision is improved, but ease of operation deteriorates due to alignment requirements
Solution Approach 1:
The patent achieves angular resolution of 100 mrad through carefully designed grating parameters and optical path geometry. By optimizing the grating period, orientation, and spacing, the system attains precise angular measurement capability while the integrated design minimizes alignment sensitivity, improving ease of operation and installation flexibility
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 provides a scalable and manufacturable CMOS-compatible photodetector with improved spectral (≲30 nm) and angular (100 mrad; 5°) resolution, enabling efficient detection of visible light and adapting to different lighting conditions without the need for separate fabrication steps for each wavelength/angle setting.
Implementation Method 1
grating coupling to bound modes on a metal/dielectric interface or waveguide modes confined by a dielectric stack
Implementation Method 2
waveguide modes confined by a dielectric stack
Implementation Method 3
CMOS-compatible p-n junction technology to accommodate short penetration depths of blue photons
Implementation Method 4
slab waveguide structure with grating periods for spectral and angular filtering
Data Source
AI summary
An occupancy sensor covering a wide field in an integrated chip is disclosed. The occupancy sensor includes an array of grating coupled waveguide sensors wherein continuous wave (cw) signals monitor an ambient light field for dynamic changes on times scales of seconds, and high frequency signals map in three-dimensions of the space using time-of-flight (TOF) measurements, pixel level electronics that perform signal processing; array level electronics that perform additional signal processing; and communications and site level electronics that interface with actuators to respond to occupancy sensing.