Optical Rotary Joint with Intermediary Coating for Signal Integrity
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Solution Overview
Problem
Existing optical rotary joints face challenges in transmitting signals effectively when derotating elements are used in media other than air, as attenuation is influenced by the surrounding medium's refractive index and quality, leading to increased prism length and signal loss.
Innovation Solution
An optical rotary joint design featuring a derotating optical element, such as a Dove prism, with supplementary elements of higher refractive index and a thin layer of a lower refractive index medium on its outer surface, allowing for total reflection independent of the surrounding medium, thereby reducing attenuation and prism length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Dove prism is surrounded by air to achieve total reflection, then low attenuation is obtained, but the device cannot be used in media other than air
Solution Approach 1:
A layer of first optically transparent material is introduced between the Dove prism (second optically transparent material) and the surrounding medium. This intermediary layer acts as a mediator that enables total reflection to occur at the boundary between the Dove prism and the intermediary layer, rather than at the boundary between the Dove prism and the surrounding medium. This allows the device to function reliably in various surrounding media while maintaining the total reflection mechanism.
2Reliability
If the refractive index of the surrounding medium is increased to be safe against fluctuations, then total reflection is maintained, but the prism length must be increased
Solution Approach 1:
The invention changes the optical parameters at the critical interface by introducing the intermediary layer with specific refractive index properties. Instead of increasing the refractive index of the entire surrounding medium (which would require a longer prism), the solution modifies the local optical parameters at the reflection interface. The intermediary layer creates the necessary refractive index contrast for total reflection without requiring the light to travel through a longer path in the prism.
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 lower signal attenuation and allows for the use of derotating elements in various media, maintaining signal quality and reducing the constructional length of the prism, making it suitable for applications under high ambient pressure or with fluctuating optical properties.
Implementation Method 1
at least one thin layer of at least one second optically transparent medium provided on an outer surface of the derotating optical element directly adjacent to the at least one reflecting inner face
Data Source
AI summary
An optical rotary joint comprises means for coupling-in or coupling-out light, and an optical derotating system. The derotating system may be a Dove prism or an Abbe-Koenig prism. In order to improve reflection at a reflecting face or faces of the derotating element, the reflecting faces are coated with an optically transparent material having a refractive index that is lower than the refractive index of the derotating element. In an embodiment the derotating optical element comprises a Dove prism. Light entry and light exit faces of the Dove prism are provided with optical supplementary elements that have an optical index of refraction greater than an optical index of refraction of the Dove prism.