Ytterbium Absorber Optical Filter for High-Angle Spectral Stability
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Solution Overview
Problem
Existing optical filters face challenges in maintaining spectral transmittance stability at high incident angles, particularly in the near-infrared region, which affects the performance of solid state image sensors.
Innovation Solution
An optical filter configuration that includes an absorber with an inorganic material containing ytterbium, an absorption layer with a dye and resin, and a dielectric multilayer film, which collectively provide excellent visible light transmittance, specific near-infrared light shielding, and minimal spectral curve shift at high incident angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dielectric multilayer film is used to shield near-infrared light, then shielding properties for specific near-infrared light are improved, but the spectral transmittance curve shifts at high incident angles
Solution Approach 1:
The patent combines a dielectric multilayer film with an absorbing material containing ytterbium to create a composite optical filter structure. The dielectric multilayer film provides interference-based shielding for specific near-infrared wavelengths, while the ytterbium-containing absorbing material provides broadband absorption. This composite structure compensates for the angle-dependent spectral shift of the dielectric film, maintaining stable shielding properties at high incident angles.
2Illumination intensity
If the optical film thickness of the dielectric multilayer film is optimized for normal incidence, then transmittance for visible light is improved, but the reflection characteristics deteriorate at high incident angles
Solution Approach 1:
The patent introduces an absorbing material with specific optical parameters (ytterbium-containing material with particular absorption coefficients) to compensate for the parameter changes that occur in the dielectric multilayer film at high incident angles. The absorbing material's broadband characteristics counterbalance the angle-dependent parameter shifts in the dielectric layers, maintaining consistent optical performance across varying incident angles.
3Stability of the object's composition
If an absorbing material such as a dye is used to reduce spectral curve shift, then transmittance stability in the visible region is improved, but it is difficult to reduce shift in the near-infrared transmission region
Solution Approach 1:
The patent applies different functional materials to different wavelength regions: the dielectric multilayer film is optimized for visible light transmission with specific interference characteristics, while the ytterbium-containing absorbing material is specifically tailored to absorb in the near-infrared region (particularly around 980 nm). This local optimization of material properties for different spectral regions enables simultaneous stability in both visible and near-infrared regions.
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 optical filter achieves excellent transmittance for visible light and specific near-infrared light, while maintaining a stable spectral curve even at high incident angles, thereby enhancing the performance and reliability of imaging devices.
Implementation Method 1
an absorber including an inorganic material including ytterbium
Implementation Method 2
a dielectric multilayer film
Implementation Method 3
an absorption layer including a dye and a resin, the dye having a maximum absorption wavelength between 350 nm and 1,200 nm
Data Source
AI summary
An optical filter includes: an absorber including an inorganic material including ytterbium; an absorption layer including a dye and a resin, the dye having a maximum absorption wavelength between 350 nm and 1,200 nm; and a dielectric multilayer film. The absorber may have a flat plate shape, and the absorber may have a thickness of 3 mm or less.