Dual-band Lateral-effect Position Sensor for High-speed Tracking
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Solution Overview
Problem
Current optical sensors are unable to efficiently detect energy in multiple spectral bands and track the location of light sources moving at high velocities due to slow response times and complexity, particularly in distinguishing between different spectral components of light from various sources such as weapons or projectiles.
Innovation Solution
A dual-axis, lateral-effect position sensor with two absorber regions and a signal-processing circuit that can detect light in two wavelength bands, determining the location of a spot of light by processing photocurrents from electrodes and providing outputs associated with time-varying intensities, allowing for simultaneous detection and tracking of light sources across multiple spectral bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple cameras are used to sense multiple spectral bands, then spectral detection capability is improved, but device complexity and size increase
Solution Approach 1:
The patent combines multiple spectral band detection capabilities into a single detector by stacking multiple absorber layers (first absorber layer for first wavelength band, second absorber layer for second wavelength band) with intermediate layers, allowing one detector to perform functions that previously required multiple separate cameras
Solution Approach 2:
The detector is designed as a universal multi-functional device that can simultaneously detect multiple spectral bands (first wavelength band and second wavelength band) and provide position information for both bands, eliminating the need for separate specialized cameras for each band
2Measurement precision
If imaging cameras are used to locate light spots, then position detection is improved, but response time becomes too slow to distinguish weapon flashes
Solution Approach 1:
The patent replaces the mechanical imaging camera system with a lateral-effect position sensor that uses electrical field effects to detect light position. This substitution of detection mechanism achieves both high speed (fast response to distinguish weapon flashes) and high precision (accurate spot location) simultaneously
3Speed
If a single detector is used for position sensing, then response time is fast, but the ability to distinguish multiple spectral bands is lost
Solution Approach 1:
The detector is segmented into multiple functional layers: first absorber layer for first wavelength band, second absorber layer for second wavelength band, and intermediate layers between them. Each layer is optimized for specific wavelength bands, enabling spectral discrimination while maintaining fast response through integrated detection
Solution Approach 2:
The patent adds spectral dimension to the position detection by incorporating multiple absorber layers sensitive to different wavelength bands. This multi-dimensional approach (position + spectral band) allows the single detector to provide both location information and spectral discrimination simultaneously
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
The sensor effectively locates and tracks light sources moving at high velocities by distinguishing between different spectral components, enabling identification and tracking of sources like rockets, projectiles, and gunshots, with improved response time and reduced complexity compared to existing systems.
Implementation Method 1
a first region absorbing light of the first wavelength band and a second region absorbing light of the second wavelength band
Implementation Method 2
each absorbing region generating holes and electrons associated with the light absorbed in each band
Implementation Method 3
The detector has an energy barrier that blocks the flow of one electrical carrier type (i.e., blocking either the holes or the electrons) but that permits the flow of the other carrier type
Data Source
AI summary
Systems and methods for a multi-band position sensor and a multi-band optical detector are disclosed. This system comprises a dual-axis, lateral-effect position sensor for locating spots of light that has energy in two wavelength bands. This sensor senses the time-varying intensities of the light in each of the two wavelength bands. This sensor also provides the location of the spot of light on the light-detecting plane of the sensor. Examples are provided for light of two mid-wave infrared (MWIR) wavelength bands or of a short-wave infrared (SWIR) and a MWIR band. This sensor approach, could be applied to detect light of other wavelength bands, such as a combination of a MWIR and a long-wave infrared (LWIR) band. This concept is extended to an array of detectors for multi-band optical detection and multi-source location and tracking. Monolithic chip level fabrication of the multi-band detectors is also discussed.