Color Splitter Structure with Shifted Element Portions for Light Efficiency
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Solution Overview
Problem
Conventional color filters in display devices and image sensors have low light use efficiency due to absorption of unwanted colors, resulting in significant light loss, especially when using the RGB color filter method, where only about 33% of incident light is transmitted.
Innovation Solution
A color splitter structure with elements including titanium oxide, niobium oxide, and tantalum oxide, and an etch stop layer of silicon nitride or oxide, is used to efficiently separate light by wavelength, optimizing the positional relationship between element portions and incorporating a dielectric layer to bury the color splitter elements, enhancing light separation and transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional color filters are used to separate colors in display devices or image sensors, then color separation is achieved, but light use efficiency deteriorates due to absorption of non-target wavelengths
Solution Approach 1:
The patent replaces conventional absorption-based color filters with a diffraction-based color splitter structure. Instead of using materials that absorb non-target wavelengths (mechanical/chemical filtering), the invention uses diffraction gratings to spatially separate wavelengths through optical interference. This substitution of the underlying physical mechanism eliminates absorption losses while maintaining color separation functionality.
Solution Approach 2:
The patent changes the operational parameter from absorption to diffraction by modifying the structural parameters of the color splitter. By designing specific grating patterns, depths, and spacing in the color splitter structure, the system transforms how light interacts with the filter - from wavelength-selective absorption to angle-selective diffraction - thereby improving light use efficiency while preserving color separation.
2Measurement precision
If RGB color filter method is used in image sensors, then color imaging is achieved, but light transmission efficiency deteriorates to only about 33%
Solution Approach 1:
The patent replaces the RGB absorption-based color filter system with a diffraction-based wavelength separation system. Instead of relying on three absorbing filters that collectively transmit only 33% of incident light, the invention uses diffraction gratings to spatially route different wavelengths to different pixel types, dramatically improving light transmission efficiency while maintaining color imaging capability.
Solution Approach 2:
The patent segments the incident light into different wavelength components using diffraction gratings, directing each wavelength band to appropriate pixel regions. This segmentation approach replaces the traditional method where all pixels pass through absorbing color filters, allowing much higher overall light transmission while still achieving color discrimination through spatial separation of diffracted wavelengths.
3Ease of manufacture
If color splitter elements are aligned without shift, then manufacturing is simplified, but color separation performance for obliquely incident light deteriorates
Solution Approach 1:
The patent applies different alignment configurations to different regions of the color splitter array. Central color splitter elements use aligned configurations for manufacturing simplicity, while peripheral elements use shifted configurations optimized for oblique light incidence. This local differentiation of structural quality allows the system to maintain ease of manufacture for the majority of elements while achieving superior color separation performance in regions where oblique incidence occurs.
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 proposed solution significantly improves light use efficiency and color separation properties, particularly for obliquely incident lights, by adjusting the shift and alignment of element portions within the color splitter structure, thereby enhancing image quality and reducing light loss.
Implementation Method 1
a color splitter comprising a plurality of color splitter elements configured to divide an incident light into a plurality of exit lights according to wavelengths
Data Source
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AI summary
Provided are colour splitter structures, methods of manufacturing the colour splitter structures, image sensors including the colour splitter structures, methods of manufacturing the image sensors, and optical apparatuses including the image sensors. A colour splitter (CS10) may include a plurality of colour splitter elements (CE10) configured to divide an incident light into a plurality of exit lights according to wavelength; and at least one of the colour splitter elements (CE10) may include a first element portion (E10), a second element portion (E20) disposed to be shifted relative to the first element portion (E10) so as to partially overlap with the first element portion (E10), and an etch stop layer (ES10) provided between the first (E10) and second (E20) element portions.