Overprint Varnish for Photoluminescent Waveguide Transparency
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Solution Overview
Problem
Current light emissive displays with photoluminescent waveguides are not fully transparent when in the non-energized state due to surface texture issues, leading to unwanted light scattering and reduced transparency.
Innovation Solution
Applying an overprint varnish (OPV) to the photoluminescent printed waveguides, which reduces or eliminates surface texture, maintaining total internal reflection and ensuring the waveguides are transparent even when not energized.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If photoluminescent colorants are printed on waveguides to create light emissive displays, then the displays can produce engaging motion effects and engage alternative geometries, but the printed waveguides develop surface texture that causes unwanted light scattering and reduces transparency when non-energized
Solution Approach 1:
A clear coating is applied as an intermediary layer over the photoluminescent printed waveguide. This coating layer mediates between the textured printed surface and the surrounding environment, eliminating the surface texture effect while maintaining the underlying photoluminescent functionality. The coating acts as a smoothing intermediary that allows light to pass through without scattering, thereby restoring transparency when the waveguide is non-energized.
2Ease of manufacture
If the waveguide surface is left uncoated to maintain simplicity, then manufacturing processes remain straightforward, but the surface texture of printed waveguides causes haze and reduces transparency in the non-energized state
Solution Approach 1:
The application of a clear coating changes the optical parameters of the waveguide surface. The coating modifies the surface properties to eliminate texture-induced scattering, thereby improving transparency and visual quality. This parameter change approach allows the waveguide to transition from a hazy, textured state to a clear, smooth-appearing state without fundamentally altering the manufacturing process complexity.
3Manufacturing precision
If a coating is applied to eliminate surface texture, then transparency is improved, but the coating must not interfere with total internal reflection and light emission functionality
Solution Approach 1:
The clear coating is designed to have different optical properties at different locations and depths. At the surface level, it provides smoothing and transparency enhancement. Deeper in the coating and at the interface with the waveguide, it maintains optical continuity that preserves total internal reflection. This local differentiation of optical properties allows the coating to simultaneously improve transparency and maintain light emission functionality.
Solution Approach 2:
The coating serves as an intermediary optical layer that reconciles the conflicting requirements of surface smoothness and optical functionality. It mediates between the need for a smooth, transparent surface and the need to preserve total internal reflection, achieving both goals through its specific optical properties and positioning between the external environment and the waveguide core.
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 OPV solution enhances transparency by eliminating surface texture, reducing light scattering, and maintaining the clarity of the waveguide when not illuminated, thereby improving the visual appearance and functionality of light emissive displays.
Implementation Method 1
maintaining total internal reflection and ensuring the waveguides are transparent
Implementation Method 2
Photoluminescent printed waveguides can be produced using various photoluminescent colorants which are transparent when non-energized, yet emit color when subjected to ultraviolet, violet, or blue light energy
Data Source
Figure 1~1b
Figure 2~2b
Figure 3~3b
AI summary
The present invention comprises a light emissive display comprising one or more photoluminescent printed waveguides. The waveguides are coated with one or more layers of an overprint varnish. The overprint varnish eliminates surface texture produced by the photoluminescent printing, rendering the waveguides transparent when in the non-energized state.