Optical Sensor With Multi-Passband Filter for Compact Multispectral Detection
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Solution Overview
Problem
Conventional optical sensor devices require multiple sensors to handle different wavelengths, leading to bulkiness and high manufacturing costs due to varying responsivities and inability to filter out noise light effectively.
Innovation Solution
A single optical sensor device equipped with a multi-passband filter that filters multiple wavelengths simultaneously, using a multilayer structure of dielectric materials to achieve uniform responsivity across different wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple optical sensors are used to measure different wavelengths, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent segments the spectral filtering function into multiple discrete passbands within a single filter structure. The multi-passband filter is divided into several filtering regions, each corresponding to a specific wavelength range (e.g., green light 495-520nm, red light 620-750nm, near-infrared 750-900nm). This allows a single sensor to effectively measure multiple wavelengths by spatially separating the spectral components, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent makes a single optical sensor perform multiple measurement functions by equipping it with a multi-passband filter. The filter enables one sensor to detect multiple wavelengths (green, red, and near-infrared) that would traditionally require separate sensors. This multi-functional approach maintains measurement precision across different wavelengths while significantly reducing device complexity and the number of components required.
2Measurement precision
If multiple optical sensors are used to handle different wavelengths, then responsivity uniformity is improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the optical parameters of the filter structure to achieve uniform responsivity across different wavelengths. By carefully designing the passband characteristics, cutoff wavelengths, and transmission ratios of the multi-passband filter, the system compensates for the natural variations in sensor responsivity. This allows a single sensor to maintain consistent measurement accuracy across green, red, and near-infrared wavelengths, eliminating the need for multiple specialized sensors and reducing manufacturing costs.
3Quantity of substance
If ambient light is not filtered, then all light wavelengths are detected, but noise light from ambient sources cannot be excluded
Solution Approach 1:
The patent applies local quality by creating specific spectral transmission characteristics at different regions of the filter. The multi-passband filter has distinct passbands with high transmission for target wavelengths (green 495-520nm, red 620-750nm, near-infrared 750-900nm) and stopbands with low transmission for ambient noise wavelengths. This spatial-spectral differentiation allows the sensor to selectively detect desired light while rejecting ambient noise, maintaining comprehensive light detection capability while eliminating harmful interference.
4Volume of moving object
If a single optical sensor is used, then device miniaturization is achieved, but the sensor cannot differentiate between different wavelength responsivities
Solution Approach 1:
The patent introduces a multi-passband filter as an intermediary component between the light sources and the single optical sensor. This filter mediates the interaction by pre-processing the light spectrum, separating different wavelengths into distinct passbands before they reach the sensor. The filter's wavelength-selective transmission characteristics enable the single sensor to differentiate between green, red, and near-infrared light based on their respective passbands, achieving wavelength differentiation without requiring multiple sensors, thus enabling device miniaturization.
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 solution allows for miniaturization and cost reduction by using a single sensor with uniform responsivity, effectively filtering out noise light and ensuring accurate measurements across various wavelengths.
Implementation Method 1
a multi-passband filter formed on a top surface of the photodiode sensor, wherein the multi-passband filter has a plurality of passbands corresponding to the light of the plurality of wavelengths from the light sources
Data Source
AI summary
An optical sensor device is provided. The optical sensor device includes a carrier substrate, a plurality of light sources disposed on the carrier substrate for generating light of a plurality of wavelengths, a photodiode sensor disposed on the carrier substrate and spaced apart from the light sources at a distance, and a multi-passband filter formed on a top surface of the photodiode sensor. The multi-passband filter has a plurality of passbands corresponding to the light of the plurality of wavelengths from the light sources.