LED Array Optical Isolation Layout for Low Crosstalk Contrast
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Solution Overview
Problem
LED and pcLED arrays face challenges with high crosstalk ratios, leading to blurry images and compromised beam patterns due to photon spillage from 'ON' to 'OFF' state pixels, which affects contrast and light output.
Innovation Solution
The arrangement of optical isolation structures discontinuously along the perimeters of semiconductor LEDs in an array, with a continuous wavelength converting layer, reduces crosstalk and increases contrast while maintaining or enhancing light output by using absorptive, reflective, or light scattering materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If continuous optical isolation structures are used along LED perimeters, then crosstalk is reduced, but light output is lost
Solution Approach 1:
The optical isolation structures are segmented into discrete portions rather than continuous structures. Each isolation structure is positioned at specific locations along the LED perimeter where crosstalk is most problematic, typically at corners or edges adjacent to inactive pixels. This segmentation approach blocks photon spillage paths that cause crosstalk while preserving light emission from active pixels that would otherwise be blocked by continuous isolation structures.
Solution Approach 2:
Optical isolation structures are applied locally at specific perimeter locations rather than uniformly along the entire LED perimeter. The isolation structures are strategically positioned based on the local crosstalk risk - for example, at corners where photons can spill to adjacent inactive pixels, or along edges where crosstalk is measured to be significant. This local application reduces overall light loss while maintaining crosstalk suppression where needed.
2Illumination intensity
If optical isolation structures are placed along LED perimeters, then contrast is improved, but device complexity increases
Solution Approach 1:
The optical isolation structures are merged with existing LED fabrication processes and structures. The isolation structures are formed using the same semiconductor fabrication techniques as the LED arrays themselves, such as depositing dielectric materials during the LED manufacturing process. This integration approach improves contrast through localized isolation while avoiding the complexity of adding separate, post-fabrication isolation components.
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 configuration effectively minimizes crosstalk and enhances contrast between adjacent pixels, improving image clarity and light efficiency compared to continuous optical isolation structures.
Implementation Method 1
using absorptive, reflective, or light scattering materials
Implementation Method 2
using absorptive, reflective, or light scattering materials
Implementation Method 3
using absorptive, reflective, or light scattering materials
Implementation Method 4
a continuous layer (e.g., a continuous wavelength converting layer) comprising a first surface through which light is emitted from the light emitting device
Data Source
AI summary
A light emitting device comprises at least two semiconductor LEDs arranged in an array with each semiconductor LED comprising a light emitting surface with boundaries defined by a perimeter, a continuous layer comprising a first surface through which light is emitted from the light emitting device during operation and an oppositely positioned second surface disposed on or adjacent to the array and extending over the light emitting surfaces of the semiconductor LEDs, and a plurality of optical isolation structures arranged in the continuous layer in a discontinuous manner along the perimeters of the light emitting surfaces between adjacent LEDs in the array.