Index Bridging Layer for Fluorescent Display Intensity Uniformity
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Solution Overview
Problem
Scanning beam display systems face non-uniformity in image formation due to unintended intensity variability in the excitation light received by the fluorescent layer, leading to artifacts and reduced image quality.
Innovation Solution
Incorporating an index bridging structure with a refractive index between that of the low-index region and the excitation filter layer, which reduces sensitivity to non-uniformities in the excitation filter layer and frequency instability, enhancing image uniformity without compromising excitation coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an excitation filter layer is used to selectively transmit excitation light and reflect visible light, then light separation efficiency is improved, but intensity variability and non-uniformity in the excitation light are amplified
Solution Approach 1:
A low-index layer is introduced as an intermediary between the excitation filter layer and the light-emitting layer. This intermediate layer acts as a buffer that decouples the excitation filter from the fluorescent layer, preventing the amplification of intensity variability while maintaining effective light separation. The low refractive index of this layer reduces the sensitivity to non-uniformities in the excitation light.
2Device complexity
If the excitation filter layer is placed close to the light-emitting layer for compact design, then device complexity is reduced, but intensity ringing artifacts increase
Solution Approach 1:
The low-index layer serves as a spatial buffer between the excitation filter layer and the light-emitting layer. This intermediary structure allows the layers to be placed close together for compact design while the low-index material prevents direct optical coupling that would cause intensity ringing artifacts, thus resolving the contradiction between compactness and artifact reduction.
3Manufacturing precision
If a low-index layer is added between the excitation filter layer and light-emitting layer, then sensitivity to non-uniformities is reduced, but device complexity increases
Solution Approach 1:
Instead of changing the entire display structure, the invention applies a low-index layer only in the specific region between the excitation filter layer and the light-emitting layer. This localized modification achieves the goal of reducing sensitivity to non-uniformities without requiring comprehensive changes to the entire device, thus minimizing the increase in device complexity.
Solution Approach 2:
The invention uses a composite layer structure combining the excitation filter layer, a low-index material layer, and the light-emitting layer. This composite structure leverages the specific optical properties of the low-index material (such as air, fluoropolymer, or silicone) to achieve reduced sensitivity to non-uniformities while maintaining a relatively simple overall structure.
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 improves the uniformity of display intensity and contrast, reduces visible artifacts, and increases the structural strength and integrity of the screen layers, while being cost-effective and adaptable to existing manufacturing processes.
Implementation Method 1
the intermediate layer includes one or more first regions in contact with the light-emitting layer, and a second region separating the one or more first regions from the excitation filter layer, and wherein the second region has a bridging refractive index between a first refractive index of the one or more first regions and a second refractive index of the excitation filter layer
Data Source
AI summary
Embodiments of fluorescent display screens having an intermediate layer between a light-emitting fluorescent layer and an excitation filter layer are disclosed. The intermediate layer includes (1) a low-index layer disposed between the light-emitting fluorescent layer and the excitation filter layer and (2) an index bridging layer disposed between the low-index layer and the excitation filter layer. The insertion of the low-index layer and the index bridging layer according to the above configuration reduces the sensitivity of the excitation coupling to the non-uniformities in the excitation filter layer and variability in the output frequency of the excitation source, leading to improved uniformity of display intensity without significant compromise in the excitation coupling efficiency. A index bridging region made of a hard coat also provides abrasion resistance and provides structure rigidity to the adjacent excitation filter layer.