Phosphor Layer With Holes For LED Optical Isolation
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Solution Overview
Problem
Manufacturing small addressable LED pixel systems with lateral light barriers is challenging due to difficulties in coating phosphor sidewalls with absorbers or distributed Bragg reflectors on segmented LEDs smaller than 500 microns, where light crosstalk between emitter segments is hard to control effectively.
Innovation Solution
A phosphor layer comprising ceramic, glass, or organic binder with arranged holes or pockets acts as a lateral light barrier, reducing light transmission between LED emitter pixels, and can be integrated into an LED package to extend over multiple pixels, using methods like mixing ceramic powder precursors, slot die coating, and sintering to create the necessary structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sidewall coating with absorbers or DBR is used to control light crosstalk, then optical isolation between LED segments is improved, but manufacturing complexity and cost increase significantly for pixels smaller than 500 microns
Solution Approach 1:
The phosphor layer is segmented into multiple discrete phosphor segments, each corresponding to an LED emitter segment. The segments are laterally separated by distance greater than the LED segment spacing, creating natural optical isolation without requiring complex sidewall coatings. This segmentation approach replaces the need for DBR or absorber coatings with a simpler geometric arrangement.
Solution Approach 2:
The solution transitions from two-dimensional sidewall coating (applying optical isolating material on vertical surfaces) to a three-dimensional arrangement where phosphor segments are laterally displaced in the horizontal plane. By separating phosphor segments in the lateral dimension rather than coating sidewalls, the patent achieves optical isolation through spatial arrangement rather than surface treatment.
2Area of moving object
If phosphor segments are closely spaced to achieve small pixel sizes, then device miniaturization is improved, but light crosstalk between segments increases
Solution Approach 1:
The phosphor layer is divided into discrete segments that are laterally separated from each other. Each phosphor segment is positioned to receive light from its corresponding LED emitter segment, and the lateral separation prevents light from one LED segment from exciting phosphor in adjacent segments, thereby eliminating crosstalk while maintaining small overall pixel dimensions.
Solution Approach 2:
Each phosphor segment is locally optimized to receive light only from its corresponding LED segment. The lateral displacement creates localized light interaction zones, ensuring that each phosphor segment converts only the light intended for it, while adjacent segments remain optically isolated. This local optimization maintains small pixel sizes without compromising optical isolation.
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
This solution effectively isolates LED segments by minimizing lateral light transmission, enabling precise control of light distribution in small pixel size LED arrays, improving optical isolation and addressing the limitations of existing methods.
Implementation Method 1
A phosphor layer comprising 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.