Spectral Imager Voltage-Controlled Depletion Region
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Solution Overview
Problem
Conventional cameras struggle to accurately image scenes responsive to light across a wide range of wavelengths, particularly in distinguishing between different spectral bands, which limits their ability to capture detailed spectral content and color images effectively.
Innovation Solution
A spectral imager with a semiconductor photosensor system that utilizes first and second p-n junctions to create oppositely directed electric fields, allowing the power source to control the location of a potential well within the pixel, thereby adjusting the sensitivity to different wavelength bands of light by varying the voltage applied, and using a responsivity matrix to determine the incident light spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional photosensor with fixed depletion region is used, then the device structure is simple, but the ability to distinguish different spectral bands is limited
Solution Approach 1:
The patent implements dynamic control of the depletion region depth through voltage application. By applying different voltages to the photosensor, the depletion region depth can be adjusted to match different wavelengths of light, enabling the same physical structure to dynamically adapt its spectral sensitivity. This resolves the contradiction by making the structure dynamically configurable rather than statically fixed.
Solution Approach 2:
The patent changes the electrical parameter (voltage) to control the physical parameter (depletion region depth). By varying the applied voltage, the depletion region depth is adjusted to optimize detection for different spectral bands. This parameter change approach allows a single structure to achieve multiple spectral discrimination functions without increasing physical complexity.
2Adaptability or versatility
If multiple fixed photosensors with different spectral responses are used, then comprehensive spectral coverage is achieved, but the device complexity and cost increase
Solution Approach 1:
The patent makes a single photosensor universal by enabling it to perform multiple spectral detection functions through voltage control. The same physical photosensor can be configured to detect different wavelength ranges by adjusting the depletion region depth via applied voltage. This eliminates the need for multiple specialized photosensors while maintaining comprehensive spectral coverage capability.
Solution Approach 2:
The patent introduces dynamic reconfigurability to a single photosensor, allowing it to adapt its spectral response characteristics in real-time. By dynamically adjusting the depletion region depth through voltage control, one photosensor can assume the roles of multiple fixed photosensors with different spectral responses, thereby achieving versatility without increasing the number of components.
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 enhances the responsivity of the pixels to longer wavelengths, allowing for precise registration of light across various spectral bands, enabling more accurate determination of the spectral content and color of light in the scene, improving the quality of color images captured.
Implementation Method 1
A pixel in the photosensor registers light from a region of the scene imaged on the pixel by the camera optics by accumulating electrons or holes from electron-hole pairs generated in the pixel by the incident light
Implementation Method 2
each pixel comprises first and second p-n junctions that define first and second photodiodes in the pixel and are characterized by depletion regions that respectively produce electric fields in opposite directions
Data Source
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AI summary
An embodiment of the invention provides a spectral imager (20) for imaging a scene comprising a semiconductor photosensor (21) comprising light sensitive pixels (26) and a power source (60) that applies voltage to the photosensor to control responsivity of the pixels to light incident on the pixels in different wavelengths bands of light.