Holographic Waveguide Surface Planarization for Optical Uniformity
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Solution Overview
Problem
Existing methods for manufacturing holographic waveguides struggle to compensate for nonuniform surface topography, leading to image artifacts due to light path deviations caused by surface nonuniformities.
Innovation Solution
A method involving applying a forming material coating to the substrate surfaces, bringing it into contact with a forming element having a desired surface profile, curing the coating while in contact, and releasing it to achieve surface planarization, using UV curing radiation and potentially thermal processes, with materials like photoresists and polymers, to correct surface nonuniformities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manufacturing methods are used for holographic waveguides, then production is simpler and faster, but surface nonuniformities cause light path deviations and image artifacts
Solution Approach 1:
The patent applies a planarization layer and performs surface planarization before fabricating the holographic grating structure. This preliminary action compensates for substrate nonuniformities early in the manufacturing process, preventing light path deviations and image artifacts that would otherwise require complex post-processing corrections.
Solution Approach 2:
The patent introduces a planarization layer as an intermediary between the substrate and the holographic grating. This intermediate layer acts as a mediator that compensates for surface nonuniformities, allowing the grating to be fabricated on a planarized surface without requiring the substrate itself to be perfectly flat.
2Manufacturing precision
If tight planarity tolerances are applied to avoid image artifacts, then image quality improves, but manufacturing becomes more difficult and costly
Solution Approach 1:
The patent applies surface planarization specifically to the regions where holographic gratings will be fabricated, rather than requiring the entire substrate to meet tight flatness specifications. This localized approach achieves the necessary surface quality for optical performance while reducing manufacturing complexity and cost compared to global planarization.
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 method effectively planarizes waveguide substrates, achieving flatness specifications and mitigating undesirable surface characteristics, enabling lightweight and cost-effective manufacturing of holographic waveguides for applications such as helmet visors and car windshields.
Implementation Method 1
curing the forming material coating includes applying UV curing radiation via a curing configuration selected from the group consisting of one or more UV sources distributed above the forming material coating
Implementation Method 2
curing the forming material coating includes a curing configuration selected from the group consisting of applying radiation having more than one wavelength, applying UV radiation having more than one wavelength within the UV spectrum, applying a thermal process
Data Source
AI summary
Systems and methods for compensating for nonuniform surface topography features in accordance with various embodiments of the invention are illustrated. One embodiment includes a method for manufacturing waveguide cells, the method including providing a waveguide including first and second substrates and a layer of optical recording material, and applying a surface forming process to at least one external surface of the first and second substrates. In another embodiment, applying the surface forming process includes applying a forming material coating to the at least one external surface, providing a forming element having a forming surface, bringing the forming element in physical contact with the forming material coating, curing the forming material coating while it is in contact with the forming element, and releasing the forming material coating from the forming element.