Optical Filter With Bidirectional Incremental Modules
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Solution Overview
Problem
Conventional optical filters face challenges in meeting various different requirements due to their configuration, which struggles with refractive index differences and light reflectance at specific angles.
Innovation Solution
The optical filter design includes a substrate, an adhesion layer with a refractive index less than 1.42, and a matching composite layer with N films stacked in sequence. These films consist of first, second, and third refraction layers with progressively higher refractive indices, arranged in a bidirectional incremental module configuration to adjust refractive index distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional optical filters use refraction layers with relatively large refractive index differences, then the filter structure is simpler, but the reflectance increases and it becomes challenging to meet various different requirements
Solution Approach 1:
The optical filter is divided into multiple functional layers including adhesion layer, interface layer, and optical film layer with progressively increasing refractive indices. This segmentation allows each layer to perform specific functions while collectively achieving low reflectance across wide viewing angles without requiring large refractive index differences between adjacent layers.
Solution Approach 2:
Different layers are assigned specific refractive index ranges tailored to their positions and functions. The adhesion layer has lower refractive index (1.42-1.65), the interface layer has intermediate refractive index (1.65-2.0), and the optical film layer has higher refractive index (2.0-2.4). This local optimization of refractive indices enables the filter to meet diverse optical requirements while maintaining structural simplicity.
2Device complexity
If conventional optical filters are designed for specific viewing angles, then the design is simpler, but the reflectance performance degrades at other angles especially at 60 degrees
Solution Approach 1:
The optical filter employs a dynamic gradient refractive index structure where the refractive index progressively increases from the adhesion layer through the interface layer to the optical film layer. This gradient configuration dynamically adapts to light incident at different angles, maintaining low reflectance performance at 60 degrees viewing angle while keeping the design systematic and manageable.
3Object-affected harmful factors
If the refractive index of the adhesion layer is increased to match higher-index layers, then the reflectance decreases, but the refractive index difference with substrate increases causing manufacturing challenges
Solution Approach 1:
An interface layer with intermediate refractive index (1.65-2.0) is introduced between the adhesion layer (lower index) and the optical film layer (higher index). This intermediary layer acts as a transition zone that gradually bridges the refractive index difference, reducing reflectance while maintaining manufacturing feasibility by avoiding abrupt index transitions.
Solution Approach 2:
The refractive index parameter is systematically varied across different layers rather than maintaining a uniform high index. The adhesion layer uses lower index materials (1.42-1.65) for ease of manufacturing, while the optical performance is achieved through the progressive index increase in subsequent layers, balancing optical performance with manufacturing constraints.
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
This design achieves a reflectance of less than 10% for incident light with wavelengths between 400 nm and 650 nm passing at 60 degrees, effectively addressing the limitations of conventional optical filters.
Implementation Method 1
a matching composite layer that is formed on the adhesion layer and that includes an N number of films stacked in sequence... Each of the first refraction layers has a first refractive index that is greater than the refractive index of the adhesion layer. Each of the second refraction layers has a second refractive index that is greater than the first refractive index. Each of the third refraction layers has a third refractive index that is greater than the second refractive index.
Implementation Method 2
In a portion of the matching composite layer between the second film and the Nth film, any two of the second refraction layers adjacent to each other sandwich one of the first refraction layers therebetween, and are sandwiched between two of the third refraction layers, so as to be jointly defined as a bidirectional incremental module.
Data Source
AI summary
An optical filter and a matching composite layer thereof are provided. The matching composite layer includes a plurality of first refraction layers, a plurality of second refraction layers, and a plurality of third refraction layers. A refractive index of the second refraction layer is greater than that of the first refraction layer, and is less than that of the third refraction layer. Any two of the second refraction layers provided with one of the first refraction layers sandwiched there-between are sandwiched between two of the third refraction layers so as to be jointly defined as a bidirectional incremental module. A number of the bidirectional incremental module included in the matching composite layer is at least M, where M is a positive integer greater than three. The M number of the bidirectional incremental modules are stacked and connected with each other.