Light Filter Structure With Graded Layer For Thin Profile
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Solution Overview
Problem
Traditional light filter structures are often thick and prone to spectrum deformation due to oblique incident light, making them unsuitable for narrow-band applications and difficult to miniaturize to a few micrometers.
Innovation Solution
A light filter structure comprising a substrate with photoelectric conversion elements, a first metal-stacking layer, a graded layer with varying thickness, a flattening layer, and a second metal-stacking layer, which acts as a Fabry-Perot resonator to reduce angle dependency and maintain a thin profile, while the graded and flattening layers control light transmission and refractive indices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a traditional light filter structure is used as a narrow-band pass filter, then the filtering function is achieved, but the structure becomes very thick
Solution Approach 1:
The patent changes the optical parameters by introducing a graded layer with continuously or non-continuously varied thickness between the metal-stacking layers. This graded thickness profile modifies the optical path and phase relationships, enabling narrow-band filtering in a thin structure by controlling constructive and destructive interference patterns without requiring the large physical thickness of traditional filters.
Solution Approach 2:
The patent employs a composite structure combining metal-stacking layers (for selective absorption and reflection) with a graded dielectric layer (for phase control and interference modulation). This composite approach integrates the advantages of both material types to achieve narrow-band filtering functionality in a compact, thin-profile configuration that overcomes the limitations of single-material traditional filters.
2Reliability
If a traditional light filter structure is used, then the filtering function is achieved, but spectrum deformation occurs due to oblique incident light
Solution Approach 1:
The graded layer introduces spatially varying thickness across the filter structure, creating local optical path differences that compensate for angle-dependent phase variations. This local quality variation ensures that oblique incident rays experience corrected optical paths, maintaining spectral accuracy and reducing deformation caused by angular incidence.
3Volume of moving object
If a traditional light filter structure is used, then the filtering function is achieved, but the size cannot be reduced to a few micrometers
Solution Approach 1:
The patent transitions from traditional planar filter designs to a vertically stratified structure with a graded layer having controlled thickness variation. This dimensional approach uses the vertical stacking of functional layers (metal-stacking, graded, and flatting layers) to achieve complex optical functionality in a compact footprint, enabling micrometer-scale filtering devices without sacrificing performance.
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 results in a light filter structure that is thin, low in angle dependency, and capable of reducing spectrum deformation, allowing for enhanced spectral resolution and miniaturization, with blue light shift minimized to less than 15 nm at 30°.
Implementation Method 1
a graded layer disposed on the first metal-stacking layer. The graded layer has a continuously or non-continuously varied thickness
Implementation Method 2
which acts as a Fabry-Perot resonator to reduce angle dependency and maintain a thin profile
Implementation Method 3
a first metal-stacking layer disposed on the substrate... a second metal-stacking layer disposed on the flatting layer
Data Source
AI summary
A light filter structure is provided. The light filter structure includes a substrate having a plurality of photoelectric conversion elements. The light filter structure also includes a first metal-stacking layer disposed on the substrate. The light filter structure further includes a graded layer disposed on the first metal-stacking layer. The graded layer has a continuously or non-continuously varied thickness. The light filter structure includes a flatting layer disposed on the graded layer. The light filter structure also includes a second metal-stacking layer disposed on the flatting layer.