Sub-aperture Light Coupling in Liquid Crystal Waveguides
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Solution Overview
Problem
The use of obliquely angled facets larger than the beamsize normal component in liquid crystal waveguides (LCWs) increases the size and cost of the devices, as they require thicker substrates to accommodate the entire beamwidth, leading to space and material inefficiencies.
Innovation Solution
Implementing sub-aperture light coupling elements, such as sawtooth-like arrangements, photonic crystal metasurfaces, or geometric-phased holograms, parallel to the LCW plane, which are smaller than the beamsize, to reduce the overall thickness of the LCW system and its light incoupler or outcoupler.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If obliquely angled facets larger than the beamsize normal component are used for light coupling, then light coupling efficiency is improved, but the device thickness and material cost increase
Solution Approach 1:
The patent divides the light coupling function into multiple sub-aperture facets instead of using a single large oblique facet. Each sub-aperture facet is smaller than the beamsize normal component, allowing parallel arrangement that maintains coupling efficiency while reducing individual facet size and overall device thickness
Solution Approach 2:
The patent transitions from a single large facet in one dimension to multiple sub-apertures arranged in parallel across the beamwidth dimension. This dimensional redistribution allows the beam to be coupled through multiple smaller apertures simultaneously, achieving the same coupling efficiency without increasing thickness
2Reliability
If obliquely angled facets larger than the beamsize normal component are used for light coupling, then light coupling efficiency is improved, but material cost increases
Solution Approach 1:
By segmenting the coupling function across multiple sub-apertures, each requiring minimal material, the total material quantity is reduced compared to a single large oblique facet, thereby lowering material costs while maintaining coupling efficiency
Solution Approach 2:
The sub-aperture facets can be implemented using thin film structures or surface modifications rather than bulk material, reducing material consumption and cost while achieving the required optical coupling function
3Length of stationary object
If sub-aperture light coupling elements are used, then device thickness is reduced, but light coupling efficiency may be compromised
Solution Approach 1:
Multiple sub-aperture facets are arranged in parallel across the beamwidth, with each facet contributing to the total coupled light. The combined effect of all sub-apertures maintains coupling efficiency equivalent to or exceeding that of a single large facet, while reducing individual and overall device thickness
Solution Approach 2:
The patent merges the light coupling function across multiple sub-aperture elements, where each sub-aperture contributes to the total coupled power. The combined effect of all sub-apertures achieves the required coupling efficiency while enabling thinner device design
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 approach reduces the thickness of the LCW system, making it more suitable for space-limited applications and lowering material costs while maintaining efficient light coupling and steering capabilities.
Implementation Method 1
a subaperture photonic crystal metasurface
Implementation Method 2
sub-aperture facets, such as in a sawtooth-like arrangement
Data Source
AI summary
A Liquid Crystal Waveguide (LCW) system can provide sub-aperture incoupling or outcoupling of light having an input wavelength and input beamsize defining an aperture characteristic of the system. A Liquid Crystal Waveguide (LCW) can include a generally planar LCW core to receive light via a light input zone for communication toward a light output zone. Sub-aperture interfacial light couplers can be planarly arranged in or parallel to the planar LCW core in the light input zone or the light output zone. Sub-aperture interfacial light couplers can include teeth, prisms, or facets, a photonic crystal metasurface, or a geometric-phased holograph (GPH)). Overall LCW thickness can be reduced, which can be helpful in space-limited applications or for reducing material costs.