Monolithic PC-LED Array Layout to Eliminate Dark Beam Lines
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Solution Overview
Problem
Existing LED arrays face issues with visible dark lines and distorted light beams due to large distances between light emitting areas and inaccurate placement, leading to manufacturing inefficiencies and reduced yield.
Innovation Solution
A monolithic LED array is developed with phosphor-converted LEDs arranged in a grid on a solid tile support, surrounded by a reflective coating with light absorbing channels, eliminating the need for flexible supports and improving placement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If LEDs are placed with large distances between them to account for reflective coating thickness and placement accuracy, then manufacturing complexity is reduced, but visible dark lines appear in the projected light beam
Solution Approach 1:
The patent applies local quality by introducing light absorbing material specifically in the channels between LEDs, while maintaining reflective coating on the support structure. This localized treatment eliminates dark lines in specific areas without requiring changes to the overall LED placement strategy, thus resolving the contradiction between ease of manufacture and light beam uniformity.
2Manufacturing precision
If rotational accuracy of LED placement is improved, then distortion of the projected beam is reduced, but manufacturing complexity and cost increase
Solution Approach 1:
The patent introduces light absorbing channels at specific locations between LEDs to correct rotational misalignment effects locally, without requiring high rotational accuracy across the entire array. This approach reduces the stringency of placement requirements while maintaining beam quality.
3Ease of operation
If flexible support material is used for LED handling, then ease of manipulation is improved, but manufacturing efficiency and yield are reduced
Solution Approach 1:
The patent extracts the support material from the final product structure, using it only as a temporary carrier during manufacturing. The flexible support enables easy handling and processing, but is completely removed before the LED array is installed, eliminating its negative impact on manufacturing efficiency and yield while retaining its benefits during the manufacturing process.
4Use of energy by moving object
If reflective coating thickness is increased to block side light emission, then light extraction efficiency is improved, but distance between light emitting areas increases causing visible dark lines
Solution Approach 1:
The patent applies local quality by differentiating the optical properties of different regions: the reflective coating maintains high thickness for light extraction efficiency, while the channels between LEDs are filled with light absorbing material to eliminate dark lines. This localized treatment resolves the contradiction between light extraction efficiency and light beam uniformity.
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 approach enhances manufacturing efficiency, reduces dark gaps, and improves light beam intensity by minimizing optical crosstalk and distortion.
Implementation Method 1
a phosphor layer affixed to a surface of the die opposite the UBM
Implementation Method 2
a reflective coating surrounding each of the PC-LEDs in place
Implementation Method 3
filling the channel with a light absorbing material
Data Source
AI summary
Described is a light emitting diode (LED) array comprising: a plurality of phosphor-converted light-emitting diodes (PC-LEDs) arranged in a grid on a solid tile support, a reflective coating surrounding PC-LEDs in place, each of the PC-LEDs comprising: a die including an under bump metallization (UBM) affixing the PC-LED to a surface of the solid tile support; a phosphor layer affixed to a surface of the die opposite the UBM, and a transparent cover layer on the phosphor layer.