Phosphor Layer Holes for LED Light Crosstalk Isolation
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Solution Overview
Problem
Manufacturing small addressable LED pixel systems with lateral light barriers is challenging, especially for LEDs smaller than 500 microns, as coating phosphor sidewalls with absorbers or distributed Bragg reflectors is difficult and costly.
Innovation Solution
A phosphor layer comprising ceramic, glass, or organic binder with arranged holes or pockets to block light transmission, creating lateral light barriers that reduce lateral light transmission, which can be integrated into LED arrays to isolate individual emitter pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If sidewall coating of absorbers or DBR is used to isolate LED segments, then light crosstalk between pixels is reduced, but manufacturing complexity and cost increase significantly for small pixel sizes
Solution Approach 1:
The phosphor layer is segmented into discrete regions corresponding to individual LED pixels, with each segment optically isolated from others. This segmentation approach replaces the need for complex sidewall coatings by creating distinct optical zones within the phosphor layer itself, thereby reducing light crosstalk without proportionally increasing manufacturing complexity.
Solution Approach 2:
The patent transitions from two-dimensional sidewall barrier approaches to a three-dimensional solution by incorporating vertical depth into the phosphor layer structure. By creating depth-varying optical properties and multi-layer configurations, the patent achieves effective light isolation without requiring precise sidewall coating at every pixel boundary.
2Object-generated harmful factors
If sidewall coating of absorbers or DBR is applied to phosphor, then lateral light transmission is blocked, but manufacturing difficulty and cost increase for pixels under 500 microns
Solution Approach 1:
The patent merges the phosphor function with the light isolation function into a single integrated layer. By incorporating optical isolation properties directly into the phosphor layer through depth-varying composition or multi-layer structures, the patent eliminates the need for separate sidewall coating processes, thereby blocking lateral light transmission while simplifying manufacturing for small pixel sizes.
Solution Approach 2:
The phosphor layer is designed to perform multiple functions simultaneously: wavelength conversion, light extraction, and lateral light isolation. This multi-functionality is achieved through depth-varying optical properties that enable the same layer to both convert LED emission to desired wavelengths and prevent lateral light crosstalk, reducing the need for additional manufacturing steps.
3Area of moving object
If phosphor segments are closely spaced to achieve small pixel sizes, then device density increases, but light crosstalk between segments increases
Solution Approach 1:
The patent applies local quality variations within the phosphor layer by creating depth-varying optical properties specific to each pixel region. Through techniques such as selective phosphor deposition, etching, or multi-layer stacking with varying compositions at different depths, each pixel location has tailored optical characteristics that prevent lateral light escape while maintaining close spacing for high density.
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 effectively isolates LED segments, allowing for precise control of light emission and reducing light crosstalk between pixels, even in small pixel size LED systems, by using a phosphor layer with strategically positioned holes or pockets to act as lateral light barriers.
Implementation Method 1
A phosphor layer can include phosphor material and at least one of a ceramic, a glass, or an organic binder
Implementation Method 2
A plurality of holes or pockets can be arranged within specific regions, areas, or internal walls of the phosphor layer to block light transmission
Data Source
AI summary
A device including a phosphor layer having a plurality of holes or pockets arranged within the phosphor layer to reduce lateral light transmission. The phosphor layer can be sized and positioned to extend over a plurality of LED emitter pixels.