Optical Isolation Element Using Prism Arrays and Louvers
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Solution Overview
Problem
Existing optical isolation devices, such as Faraday optical isolators, require large external magnetic fields and expensive materials, limiting their size and transmittance efficiency, especially in the forward direction.
Innovation Solution
An optical isolation element comprising a first optical path changing element, a light control film, and a second optical path changing element, where the first element is an inequilateral triangular prism film and the second element is an isosceles triangular prism film, with a light control film that selectively transmits light at specific angles, achieving high forward transmittance without external magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Faraday optical isolator is used, then optical isolation function is achieved, but the device requires expensive materials, large external magnetic field, and cannot be made large in size
Solution Approach 1:
The optical isolator is divided into three functional segments: a first optical path changing element (prism array), a light control film with absorptive louvers, and a second optical path changing element (prism array). Each segment performs a specific function in the optical isolation process, allowing the system to achieve the isolation effect while using simpler, less expensive materials and structures.
Solution Approach 2:
The light control film incorporates absorptive louvers with specific tilt angles (e.g., 45 degrees) that are optimized for blocking backward-propagating light. The prism arrays have specific geometric configurations (apex angles, ridge line orientations) tailored to redirect light in desired directions. This localized optimization of structural properties enables effective optical isolation without requiring complex global system design.
2Reliability
If a Faraday optical isolator is used, then optical isolation function is achieved, but forward transmittance is limited to 50%
Solution Approach 1:
The device exhibits asymmetric optical properties: in the forward direction, light passes through the first prism array, the light control film, and the second prism array with minimal obstruction (achieving 84% transmittance). In the backward direction, the same structure actively blocks light through the absorptive louvers. This asymmetric design allows high forward transmittance while maintaining effective optical isolation.
Solution Approach 2:
The light control film with absorptive louvers acts as an intermediary element between the two prism arrays. For backward-propagating light, this intermediary layer actively absorbs and blocks the light, preventing it from passing through. For forward-propagating light, the intermediary layer is positioned and oriented to minimize interference, allowing high transmittance while still providing the isolation function.
3Reliability
If a Faraday optical isolator is used, then optical isolation function is achieved, but expensive materials have to be applied
Solution Approach 1:
The patent replaces expensive Faraday rotator materials with more economical components: standard optical prisms made from common optical glass or plastic, and a light control film with absorptive louvers. These components can be manufactured using conventional techniques at lower cost, making the optical isolator more economically viable for widespread application.
Solution Approach 2:
The patent replaces the magnetic field-based Faraday rotation mechanism with a geometric-optical mechanism using prisms and absorptive louvers. This substitution eliminates the need for expensive magneto-optic materials and external magnetic field generation systems, reducing both material costs and device complexity while achieving the same optical isolation function.
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 high transmittance in the forward direction while significantly reducing transmittance in the backward direction, achieving an optical isolation ratio of approximately 3, with forward transmittance of 84% and backward transmittance of 42%, suitable for various applications including optical communication, security, and display enhancement.
Implementation Method 1
The first optical path changing element is a film-shaped element composed of an inequilateral triangular prism array... the light incident at an incident angle of a first angle can be emitted at an output angle of a second angle
Implementation Method 2
The light control film is configured such that the light incident on the light entrance surface or the light exit surface at an incident angle of the second angle is transmitted and the light incident on the light entrance surface or the light exit surface at an incident angle of a third angle is absorbed or reflected
Implementation Method 3
The second optical path changing element is configured such that the light incident on the light entrance surface at an incident angle of the second angle can be emitted to a fourth angle, and the light incident on the light exit surface at the fourth angle is emitted at output angles of the second angle or the third angle
Data Source
Figure 1
AI summary
The present application relates to an optical isolation element. The optical isolation element of the present application has excellent forward transmittance, which may require no separate external force. Such an optical isolation element can be applied to various applications such as the field of optical communication or laser optics, the field of security or privacy protection, brightness enhancement of displays, or military hiding and covering.