Polarized Wave Separation Element Wide Incident Angle
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Solution Overview
Problem
Conventional polarized wave separation elements using dielectric multilayer films face challenges in effectively handling wide incident angles without requiring complex structural birefringent layers.
Innovation Solution
A polarized wave separation element is designed with a multilayer film alternately stacking low and high refractive index substances, where specific optical film thickness ratios and patterns are used to unify the amplitude of incident light, allowing for efficient separation of polarized waves over a wide incident angle range without needing structural birefringent layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional dielectric multilayer film is used for polarized wave separation, then the structure is simple, but the incident angle range is limited and cannot handle wide angles effectively
Solution Approach 1:
The patent applies local quality by creating specific stacks with distinct optical thickness ratios (Hn:Ln ≥ 2.0) at particular positions within the multilayer film. These localized stacks with optimized thickness ratios are strategically placed to handle specific angle ranges, allowing the overall film to accommodate wide incident angles while maintaining a relatively simple structure. Each stack's local optical properties are tuned to contribute to the global angular adaptability.
Solution Approach 2:
The multilayer film is segmented into multiple stacks, where each stack consists of alternating high and low refractive index layers with specific optical thickness ratios. By dividing the film into discrete stacks with different Hn:Ln ratios, the patent enables each segment to handle different incident angle ranges, collectively achieving wide-angle performance without requiring an overly complex monolithic structure.
2Adaptability or versatility
If structural birefringent layers are added to handle wide incident angles, then the angular range improves, but the device complexity increases
Solution Approach 1:
The patent achieves wide incident angle handling by changing the optical thickness parameters (Hn and Ln) of the dielectric layers rather than introducing birefringent materials. By adjusting the thickness ratios to satisfy Hn:Ln ≥ 2.0 in specific stacks, the patent modifies the optical path difference and phase relationships to maintain polarization separation across wide angles, avoiding the need for complex birefringent layer structures.
Solution Approach 2:
The patent uses composite dielectric materials with different refractive indices (high index nh and low index nl) arranged in alternating stacks. This composite structure, with carefully controlled thickness ratios, creates the necessary optical path differences to handle wide incident angles without requiring birefringent materials, thus maintaining structural simplicity while achieving the desired angular adaptability.
3Ease of manufacture
If the multilayer film uses uniform thickness layers, then the manufacturing is easier, but the transmissivity characteristics deteriorate at wide angles
Solution Approach 1:
The patent applies local quality by specifying that only certain stacks (those with higher order numbers) need to satisfy the Hn:Ln ≥ 2.0 ratio, while other stacks can have different ratios. This localized optimization allows stacks critical for wide-angle performance to have precise thickness control, while other stacks can be manufactured with more tolerance, balancing manufacturing ease with optical performance.
Solution Approach 2:
The patent implements partial optimization by requiring the Hn:Ln ≥ 2.0 condition only for specific stacks rather than all stacks in the multilayer film. This partial action approach focuses manufacturing precision where it is most needed (in stacks that critically affect wide-angle transmissivity) while allowing greater flexibility in other stacks, thus maintaining good transmissivity characteristics without making the entire manufacturing process excessively difficult.
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 enables effective separation of polarized waves across a wide incident angle range, achieving good transmissivity characteristics with a simple multilayer film structure, suitable for applications like endoscopes, microscopes, and other optical systems.
Implementation Method 1
a second stack, a third stack, and a fourth stack which satisfy the above-mentioned conditional expression (1), wherein an n-th stack from the first substrate is named as an n-th stack, Ln is an optical film thickness of the low refractive index substance of the n-th stack, and Hn is an optical film thickness of the high refractive index substance of the n-th stack
Implementation Method 2
a polarized wave separation element includes a multilayer film between a first substrate and a second substrate, the multilayer film being formed by alternately stacking a relatively low refractive index substance and a relatively high refractive index
Implementation Method 3
the multilayer film being formed by alternately stacking a relatively low refractive index substance and a relatively high refractive index
Data Source
AI summary
A polarized wave separation element includes a multilayer film between a first substrate and a second substrate, the multilayer film being formed by alternately stacking a relatively low refractive index substance and a relatively high refractive index. Define a pair of a low refractive index substance layer and a high refractive index substance layer as a stack, half or more than half of stacks in the multilayer film satisfy following conditional expression (1), where an nth stack from the first substrate is named as an nth stack, Ln is an optical film thickness of the low refractive index substance of the nth stack, and Hn is an optical film thickness of the high refractive index substance of the nth stack, H1:L1=Hn:Ln (1), the polarized wave separation element further comprises a plurality of stacks in the multilayer film satisfying following conditional expressions (2a) and (2b): Hn=H1×(a+(n−2)×b) (2a), Ln=L1×(a+(n−2)×b) (2b), where a constant a is 1.1 to 1.3, and a constant b is 0.3 to 0.6.