Integrated Mold for AR Waveguide Anti-Reflective Structures
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Solution Overview
Problem
Conventional augmented reality eyewear displays face limitations due to optical, aesthetic, manufacturing, thickness, and field of view constraints, along with high reflection issues from grating surfaces leading to undesirable optical effects and increased costs for anti-reflective coatings.
Innovation Solution
The implementation of moth eye nanopillar anti-reflective structures nanoimprinted onto waveguides using integrated molds, which simultaneously form diffractive optical and anti-reflective structures, reducing reflections and manufacturing costs by decoupling precision requirements for different molds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional anti-reflective coatings are applied to waveguide surfaces, then reflection is reduced, but manufacturing complexity and cost increase due to multiple lithography steps
Solution Approach 1:
The patent combines the formation of diffractive optical structures and anti-reflective structures into a single nanoimprinting step using an integrated mold. The mold contains both diffractive optical element patterns and anti-reflective nanopillar patterns, allowing simultaneous creation of both structures on the waveguide surface without requiring separate lithography processes for each.
Solution Approach 2:
The integrated mold serves multiple functions: it acts as both the diffractive optical element pattern source and the anti-reflective structure pattern source. A single mold performs what previously required multiple specialized tools, simplifying the manufacturing workflow while achieving both optical functionality and anti-reflective properties.
2Manufacturing precision
If separate molds are used for diffractive optical structures and anti-reflective structures, then manufacturing precision can be maintained, but production time and cost increase
Solution Approach 1:
The patent merges the patterning operations for diffractive optical structures and anti-reflective structures into a single parallel nanoimprinting operation. Both structures are formed simultaneously in one step, eliminating the sequential processing required when using separate molds, thereby doubling the production efficiency without compromising precision.
3Object-affected harmful factors
If multiple layers of anti-reflective coating are applied, then reflection reduction improves, but manufacturing time and cost increase
Solution Approach 1:
The anti-reflective nanopillar structures are formed as integral parts of the waveguide surface during the initial manufacturing process rather than being applied as separate coating layers afterward. This preliminary formation eliminates the need for multiple sequential coating applications and associated drying/curing steps, reducing total manufacturing time while achieving the desired anti-reflective effect.
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 enhances image quality by minimizing reflections and reducing production costs, while maintaining the precision needed for diffractive optical structures, thus improving the user experience and efficiency in producing augmented reality eyewear displays.
Implementation Method 1
anti-reflective coatings and structures are often applied to one or more surfaces of an augmented reality display
Implementation Method 2
The anti-reflection coatings are typically applied by block lithography, which involves an expensive process of depositing layers of thin films on a substrate of the waveguide
Implementation Method 3
Once the light beams have been coupled into the waveguide, the light beams are 'guided' through the substrate, typically by multiple instances of total internal reflection
Implementation Method 4
light from an image source is coupled into a light guide substrate, generally referred to as a waveguide, by an input optical coupling such as an in-coupling grating
Data Source
AI summary
Methods and apparatuses for applying anti-reflective structures to a waveguide of an augmented reality display device include producing two initial molds: one formed with high precision for diffractive optical structures, and one formed with lower precision for anti-reflective structures. The two initial molds are imprinted into a single resist layer to form an integrated mold, which is then usable to simultaneously form both diffractive optical structures and anti-reflective structures. Accordingly, the cost of producing the anti-reflective structures is minimized while the efficiency of forming the diffractive optical structures and anti-reflective structures is maximized.