Optical Filter Reference Regions for Accurate Color Measurement
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Solution Overview
Problem
Existing image sensors that divide the wavelength band into only three sections (red, green, and blue) limit the accuracy of color expression and object recognition in image analysis, and integration of spectral filters with semiconductor chips is still under development.
Innovation Solution
An optical filter with an active filter region including spectral and polarizing filters, and a reference filter region with gray, black, and transparent filters, allowing for more precise light measurement by using filters with varying transmittances to enhance color expression and object recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If image sensors divide wavelength band into only three sections (R, G, B), then the device complexity is low, but the measurement precision of color expression and object recognition is limited
Solution Approach 1:
The optical filter is divided into multiple filter regions (first filter region with spectral filter, second filter region with polarizing filter, third filter region with reference filter) that are arranged in an array pattern. Each region processes different aspects of light (wavelength, polarization, intensity reference), enabling multi-dimensional spectral analysis while maintaining a relatively simple integrated structure on the semiconductor chip.
Solution Approach 2:
The patent combines spectral filtering, polarizing filtering, and reference intensity measurement into a single integrated optical filter structure that is directly mounted on the semiconductor chip. This merging of multiple filter functions into one component achieves high measurement precision without requiring separate dedicated cameras or complex optical elements, thus resolving the contradiction between measurement precision and device complexity.
2Device complexity
If spectral filters are integrated with semiconductor chip, then the device complexity is reduced, but the manufacturing precision is challenging
Solution Approach 1:
The reference filter region includes multiple filters (black filter, gray filter, transparent filter) with different transmittance characteristics arranged in specific locations. The gray filter has a transmittance between that of the black and transparent filters, creating local variations in light transmission that enable precise measurement and compensation without requiring high overall manufacturing precision across the entire filter structure.
Solution Approach 2:
The reference filter region provides reference light intensity measurements that are used to compensate for variations in incident light intensity. By comparing the light intensity measured through the spectral filter with the reference intensity from the reference filter region, the system can correct for manufacturing variations and maintain measurement accuracy, thus reducing the impact of manufacturing precision challenges.
3Measurement precision
If reference filter region with multiple transmittance levels is added, then the measurement precision of light intensity is improved, but the device complexity increases
Solution Approach 1:
The reference filter region serves multiple functions simultaneously: it provides reference intensity measurements for compensation, enables measurement of light intensity across different transmittance levels (black, gray, transparent filters), and acts as a calibration reference. This multi-functionality allows the system to achieve high measurement precision without adding proportionally more complex structures, as one region performs multiple measurement tasks.
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 optical filter enables accurate measurement of light intensity across different wavelength bands, improving color expression and object recognition in image sensors.
Implementation Method 1
an active filter region including at least one of a spectral filter and a polarizing filter
Implementation Method 2
an active filter region including at least one of a spectral filter and a polarizing filter
Implementation Method 3
the reference filter region includes a gray filter and at least one of a black filter and a transparent filter, wherein the gray filter has a transmittance that is higher than a transmittance of the black filter and lower than a transmittance of the transparent filter
Data Source
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AI summary
An optical filter includes an active filter region including at least one of a spectral filter and a polarizing filter; and a reference filter region configured to sense an amount of light passing through the active filter region, wherein the reference filter region includes a gray filter and at least one of a black filter and a transparent filter, wherein the gray filter has a transmittance that is higher than a transmittance of the black filter and lower than a transmittance of the transparent filter.