Freeform Beamsplitter for Multi-Spectral Aberration Correction
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Solution Overview
Problem
Conventional parallel plate beamsplitters in multi-spectral telescopes suffer from residual on-axis aberrations that cannot be completely corrected using rotationally symmetric imaging lenses, necessitating complex alignment techniques like tilting and decentering of optical components.
Innovation Solution
A beamsplitter with a freeform, non-axisymmetric second surface is used to mitigate aberrations, allowing for the transmission and reflection of multi-spectral light, eliminating the need for subsequent aberration correction in the optical path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a parallel plate beamsplitter is used to separate multi-spectral light, then the spectral separation function is achieved, but non-axiosymmetric aberrations are introduced that cannot be completely corrected by rotationally symmetric imaging lenses
Solution Approach 1:
The patent applies asymmetry by transforming the traditional rotationally symmetric parallel plate beamsplitter into an asymmetric freeform beamsplitter. The freeform surface is specifically designed with non-axiosymmetric geometry to compensate for the aberrations introduced by the beamsplitting function, thereby achieving both spectral separation and aberration correction in a single component.
Solution Approach 2:
The patent merges the beamsplitting function with the aberration correction function into a single freeform beamsplitter component. By integrating the freeform surface directly onto the beamsplitter substrate, the design eliminates the need for separate correction optics and complex alignment procedures, combining multiple functions into one element.
2Manufacturing precision
If conventional alignment techniques are used to compensate for residual aberrations, then aberration correction is attempted, but the system requires complex sequential tilting and decentering of optical components
Solution Approach 1:
The patent extracts the aberration correction function from the alignment procedure and integrates it directly into the beamsplitter's freeform surface geometry. This eliminates the need for complex sequential tilting and decentering operations, as the correction is built into the component itself rather than requiring post-assembly adjustment.
Solution Approach 2:
The freeform beamsplitter is designed to self-correct aberrations through its inherent freeform surface geometry. The component performs aberration correction automatically as light passes through it, without requiring external alignment procedures or additional active adjustment mechanisms, thereby simplifying the overall system.
3Manufacturing precision
If a wedge is applied to the beamsplitter surface to minimize aberrations, then some aberration reduction is achieved, but residual on-axis aberrations remain
Solution Approach 1:
The patent extends the concept of curvature by using a freeform surface that incorporates complex non-spherical geometry. This freeform surface is designed to provide the precise wavefront correction needed to eliminate residual on-axis aberrations, going beyond simple wedge corrections and achieving complete aberration compensation.
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 freeform surface effectively corrects aberrations in the transmitted band, enabling axially symmetric imaging without the need for tilting or decentering, making the system modular and improving image quality in multi-spectral telescopes.
Implementation Method 1
a first surface configured to receive a beam of multi-spectral light, to reflect a first band of the multi-spectral light
Implementation Method 2
to transmit a second band of the multi-spectral light through the optical substrate
Implementation Method 3
The second surface is a freeform surface, e.g. has a freeform shape... The freeform surface can be configured to mitigate aberration in the second band emitted from the second surface
Data Source
AI summary
A beamsplitter includes an optical substrate with a first surface configured to receive a beam of multi-spectral light, to reflect a first band of the multi-spectral light and to transmit a second band of the multi-spectral light through the optical substrate to be emitted from a second surface of the optical substrate opposite the first surface. The second surface is a freeform surface. A system includes a telescope configured to focus multi-spectral light into a beam. The system also includes a beamsplitter as described above optically coupled to the telescope so the first surface of the beamsplitter is configured to receive the beam of multi-spectral light from the telescope.