Photosensor Well Structures for Visible Infrared Noise Isolation
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Solution Overview
Problem
Silicon-based photosensors face challenges in distinguishing between visible and infrared light due to their wide spectral range, leading to noise in sensed images, especially in environments where both types of light are present.
Innovation Solution
A photosensor device comprising first and second well structures on substrates, with a light shielding layer covering part of the first well structures to isolate them and expose others, generating distinct photocurrents which are processed to obtain spectrum signals, including an infrared spectrum signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a silicon-based photosensor is used to sense visible light, then it can detect visible light effectively, but it also receives infrared light causing noise in the sensed image
Solution Approach 1:
The photosensor device is divided into two separate substrates: a first substrate for detecting visible light and a second substrate for detecting infrared light. This segmentation allows each substrate to specialize in one wavelength range, preventing cross-contamination of signals and eliminating noise in the visible light detection caused by infrared light
Solution Approach 2:
A light shielding layer is introduced as an intermediary component between the first substrate (visible light detector) and the second substrate (infrared detector). This layer blocks infrared light from reaching the first substrate while allowing visible light to pass through, effectively filtering out harmful infrared noise from the visible light detection path
2Measurement precision
If a silicon-based photosensor is used to sense infrared light, then it can detect infrared light, but the image has high noise ratio due to retrieved visible light
Solution Approach 1:
The photosensor device is divided into two separate substrates: a first substrate for detecting visible light and a second substrate for detecting infrared light. This segmentation allows each substrate to specialize in one wavelength range, preventing cross-contamination of signals and eliminating noise in the infrared light detection caused by visible light
Solution Approach 2:
A light shielding layer is introduced as an intermediary component between the first substrate (visible light detector) and the second substrate (infrared detector). This layer blocks visible light from reaching the second substrate while allowing infrared light to pass through, effectively filtering out harmful visible light noise from the infrared detection path
3Measurement precision
If the total surface area of second well structures is made equal to the total surface area of first well structures, then the device can accurately process spectrum signals, but the device complexity increases
Solution Approach 1:
The patent specifies that the total surface area of the second well structures on the second substrate should be substantially equal to the total surface area of the first well structures on the first substrate. This parameter matching ensures that the photocurrent signals from both substrates can be accurately compared and processed to generate precise spectrum signals, while the complexity is managed through systematic design
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 device effectively separates and processes photocurrents to reduce noise, enabling accurate sensing of incident light spectra by isolating the impact of nearby well structures and ensuring equal surface area exposure for both substrates.
Implementation Method 1
the first well structure exposed by the light shielding layer is capable of generating a first photocurrent according to illumination of an incident light
Implementation Method 2
The second well structures are disposed in a second substrate and capable of generating a second photocurrent according to illumination of the incident light
Data Source
AI summary
A photosensor device includes a plurality of first well structures, a light shielding layer, and a plurality of second well structures. The first well structures are disposed in a substrate. The light shielding layer disposed is on the substrate; it covers a portion of the first well structures and exposes the rest portion of the first well structures. The covered first well structures are adjacent to the exposed first well structures exposed. The exposed first well structures generate a first photocurrent according to incident light. The second well structures generate a second photocurrent according to incident light. A total surface area of the second well structures is substantially equal to a total surface area of the exposed first well structures. A method for determining the incident light is also provided.