LED Sidewall Layers for Light Extraction and Crosstalk Reduction
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Solution Overview
Problem
Conventional LED packaging limitations, such as spacing constraints and cross-talk issues, hinder the production of high-quality light with desired emission characteristics in closely-spaced LED arrays, and existing technologies struggle to maximize light extraction efficiency due to internal reflection.
Innovation Solution
The implementation of a sidewall arrangement around LED chips comprising a reflective inner layer and an absorptive outer layer, without the need for a submount or lead frame, to enhance light output, sharpness, and contrast, using laminated light-altering materials with specific thicknesses and properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional LED packaging is used with submount or lead frame, then structural support is provided, but spacing constraints and cross-talk issues occur in closely-spaced LED arrays
Solution Approach 1:
The patent removes the conventional submount and lead frame structures from the LED package, extracting only the essential functional elements. This extraction eliminates the spacing constraints and cross-talk issues associated with traditional packaging while maintaining structural support through alternative means (direct mounting of LED chip on circuit board).
Solution Approach 2:
The patent applies different light-altering properties to different regions of the LED package. The sidewall region is specifically treated with light-altering materials to control light emission characteristics and reduce cross-talk, while other regions maintain their original functions. This localized modification addresses cross-talk without affecting overall package structure.
2Productivity
If multiple LED emitters are arranged in close proximity, then desired light emissions can be combined, but light extraction efficiency is limited by internal reflection
Solution Approach 1:
The patent converts the harmful effect of internal reflection into a beneficial outcome by applying light-altering materials to the sidewalls. These materials redirect photons that would otherwise be internally reflected and lost, converting them into useful light emission that contributes to the desired light output while reducing energy loss.
Solution Approach 2:
The patent uses composite light-altering materials applied to the LED sidewalls that combine multiple functional properties. These composite materials are designed to simultaneously address light extraction efficiency, emission characteristics, and cross-talk reduction, optimizing overall light output while minimizing energy loss to internal reflection.
3Use of energy by moving object
If light-altering materials are applied to LED sidewalls, then light output and efficiency are improved, but device complexity increases
Solution Approach 1:
The patent divides the light-altering functionality into discrete segments applied to different regions of the LED sidewalls. Rather than applying a complex uniform coating, the sidewalls are segmented into zones with different light-altering properties, simplifying the overall structure while maintaining high light extraction efficiency through targeted material placement.
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 improves light output, sharpness, and contrast in LED devices, enabling their use in closely-spaced arrays by reducing cross-talk and maximizing light extraction efficiency, suitable for applications like automotive lighting and displays.
Implementation Method 1
the inner layer can be reflective so as to improve the light output and/or efficiency of the LED chip
Implementation Method 2
the outer layer can be absorptive so as to avoid interaction and/or crosstalk with neighboring LED chips
Data Source
AI summary
Solid-state lighting devices, and more particularly sidewall arrangements for light-emitting devices such as light-emitting diodes (LEDs) are disclosed. LED devices may include light-altering materials that are provided around peripheral sidewalls of LED chips without the need for a supporting submount or lead frame. The side layer around the peripheral sidewall of the LED chip can include an inner layer and an outer layer, each with different light altering properties. For example, the inner layer can be reflective so as to improve the light output and/or efficiency of the LED chip, while the outer layer can be absorptive so as to avoid interaction and/or crosstalk with neighboring LED chips. By having a reflective inner layer, and an absorptive outer layer, light output, sharpness, and contrast can be improved.