Photoluminescent Waveguide Display With Light Filter For Dark Background
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Solution Overview
Problem
Photoluminescent light emissive displays face issues with limited useful life due to fading, non-transparent colorants causing discoloration, high energy consumption for white backgrounds, and the need for dark backgrounds for image contrast, which restricts display size and artwork options.
Innovation Solution
Incorporating a light filter between the photoluminescent waveguide and a transparency or physical object layer to provide a dark background, allowing for extended display life and reduced energy consumption, while enabling the display of images with light-colored features by adjusting ink content and using additional illumination when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If photoluminescent phosphors are used to create emissive displays, then color emission is achieved, but darkness cannot be created and white background requires excessive energy
Solution Approach 1:
The display is segmented into multiple independently controllable waveguide layers, each capable of displaying different content. This allows selective activation of only the necessary layers for displaying light-colored imagery, reducing overall energy consumption while maintaining color emission capabilities.
Solution Approach 2:
Different regions of the display utilize different waveguide layers with varying phosphor compositions optimized for specific color requirements. This local optimization allows efficient energy use by activating only the specific layers needed for the current display content.
2Manufacturing precision
If photoluminescent inks are made more transparent to reduce discoloration, then color accuracy improves, but emission intensity decreases
Solution Approach 1:
The system uses asymmetric layer configuration where the first waveguide layer contains phosphors optimized for transparency and color accuracy, while the second waveguide layer contains phosphors optimized for emission intensity. This asymmetric division allows each layer to excel at its primary function without compromising the other.
Solution Approach 2:
The solution moves from a single-layer system to a multi-layer stacked configuration, adding the dimension of vertical layering. This allows independent optimization of each layer's properties (transparency vs. intensity) and provides additive color mixing capabilities.
3Adaptability or versatility
If multiple waveguide layers are stacked to extend display content, then display versatility increases, but system complexity increases
Solution Approach 1:
Multiple waveguide layers are optically combined into a single integrated display system where light from a common source propagates through all layers simultaneously. This merging approach allows versatile multi-layer display content while maintaining a relatively simple overall system architecture.
Solution Approach 2:
The stacked waveguide system provides multi-functionality by enabling display of both dark-background imagery (using single layer activation) and light-colored imagery (using multiple layers simultaneously), as well as enabling extended display content beyond what a single layer could provide.
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 solution extends the useful life of photoluminescent displays, allows for the creation of light-colored imagery without significant color loss, and reduces energy consumption by maintaining a dark background for improved contrast and visibility.
Implementation Method 1
Photoluminescent printed waveguides can be produced using various photoluminescent colorants which are transparent when non-energized, yet emit color when subjected to ultra-violet, violet, or blue light energy.
Implementation Method 2
Emissive RGB printed waveguides dependent on total internal reflection which convert incident energy of one wavelength to emissive color
Data Source
Figure 1A~2B
Figure 1B~3B
Figure 3A~4B
AI summary
A display 10 with a first emissive image 16 and a second image 24. The display includes a waveguide 12 that includes an image 16 formed from photoluminescent dyes on a surface of the waveguide which is activated by a first light source 14. A second light source 22 behind said waveguide produces a second image 24. A light filter 18 is positioned between the waveguide 12 and the second light source 22. The second light source 22 can illuminate a transparency, such as a translight, or a physical object providing an image that is viewable from the display when the second light source is illuminated and the first light source is not illuminated. The first image 16 is viewable when the first light source 14 associated with the waveguide is activated, emitting, for example, an ultraviolet light that activates the photoluminescent dyes, causing the first image to be viewable. The light filter 18 behind the waveguide enhances the quality of the emissive image and prevents the image on the transparency or the physical object from being seen when the second light source is not illuminated.