Rectangular Optical Waveguide Aperture Multipliers With Partial Reflection
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Solution Overview
Problem
Existing optical aperture multipliers face challenges in efficiently expanding two-dimensional optical apertures while simplifying fabrication processes and reducing manufacturing costs.
Innovation Solution
The use of a rectangular optical waveguide optically coupled with a thin slab-type optical waveguide, where the coupling-in configuration is deployed on a portion of the interface with different optical characteristics, and the rectangular waveguide employs a partially reflective surface instead of internal reflective surfaces, simplifying fabrication and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal reflective surfaces are used in the rectangular waveguide, then optical coupling efficiency is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the reflective function from internal surfaces and relocates it to the external interface between waveguides. The rectangular waveguide uses its external bottom face with a reflective coating instead of internal reflective surfaces, simplifying manufacturing while maintaining optical coupling efficiency.
Solution Approach 2:
The patent introduces an intermediate reflective coating on the external interface between the rectangular and slab waveguides. This coating acts as a mediator that enables efficient optical coupling between the two waveguides without requiring complex internal reflective structures.
2Area of stationary object
If traditional optical aperture expansion methods are used, then aperture multiplication is achieved, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent merges the functions of aperture expansion and optical guidance into a single integrated waveguide system. The rectangular waveguide with external reflective coating combines light guidance and aperture multiplication functions, eliminating the need for separate internal reflective components and reducing manufacturing cost.
Solution Approach 2:
The patent changes the optical parameters at the waveguide interface by applying a reflective coating with specific reflectivity characteristics. This parameter change enables efficient optical coupling and aperture expansion while using standard manufacturing processes for applying coatings.
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 configuration enhances aperture expansion in two dimensions while simplifying the manufacturing process and reducing costs, achieving efficient optical coupling and improved image quality.
Implementation Method 1
The rectangular waveguide has two pairs of parallel faces (that form a rectangular cross-section) and is configured to guide light by four-fold internal reflection at the two pairs of parallel faces
Implementation Method 2
a set of partially reflective surfaces internal to the rectangular waveguide... a proportion of intensity of the image is reflected at the first set of internal surfaces so as to be coupled into the second waveguide
Implementation Method 3
The second waveguide has a pair of parallel faces and is configured to guide the coupled-in light by internal reflection at the pair of parallel faces
Implementation Method 4
the optical coupling-in configuration is deployed on a portion of the front or back side of the rectangular waveguide that adjoins a second region of the interface between the two waveguides that has a different optical characteristic from a first region of the interface. In one set of embodiments, the first region of the interface includes a reflective coating, and the second region is either uncoated or includes a low index material or coating
Data Source
Figure 1A~1B
Figure 1C~2
Figure 3~4C
AI summary
An optical device includes a first waveguide, having parallel first and second faces and parallel third and fourth faces forming a rectangular cross-section, that guides light by four-fold internal reflection and is associated with a coupling-out configuration that couples light out of the first waveguide into a second waveguide. The first or second face is subdivided into first and second regions having different optical characteristics. The optical device also includes a coupling-in configuration having a surface that transmits light into the first waveguide. The surface is deployed in association with a portion of the third or fourth face adjoining the second region such that an edge associated with the surface trims an input collimated image in a first dimension, and a boundary between the first and second regions trims the input collimated image in a second dimension to produce a trimmed collimated image that advances by four-fold internal reflection.