LED Array Patterned Bus Electrode Contrast Ratio
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Solution Overview
Problem
Existing light emitting diode (LED) arrays face challenges in achieving high contrast ratios and efficient light emission due to reflectance from ambient light and higher resistance issues in current electrode configurations.
Innovation Solution
A light emitting device configuration featuring a backplane with an array of LEDs, a dielectric matrix layer, a transparent conductive layer, and a patterned bus electrode layer with openings, where the patterned bus electrode layer is electrically shorted to the transparent conductive layer and includes higher light absorption materials to reduce reflectance and enhance electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a transparent conductive layer is used to reduce ambient light reflectance, then contrast ratio is improved, but electrical resistance increases
Solution Approach 1:
The patent combines a transparent conductive layer with a patterned bus electrode layer to create a hybrid electrode structure. The transparent conductive layer provides low reflectance for high contrast ratio, while the patterned bus electrode layer with metal traces provides low resistance pathways. The two layers are electrically connected through contact openings, merging their functions to simultaneously achieve both high contrast ratio and low electrical resistance.
Solution Approach 2:
The electrode structure uses composite materials by stacking a transparent conductive material (such as ITO or transparent conductive oxide) with a metallic patterned electrode material. This composite structure leverages the optical properties of the transparent material (low reflectance) and the electrical properties of the metal (high conductivity), resolving the contradiction between contrast ratio and electrical resistance.
2Illumination intensity
If a patterned bus electrode layer with openings is used to reduce reflectance, then contrast ratio is improved, but manufacturing complexity increases
Solution Approach 1:
The bus electrode is segmented into a patterned structure with multiple openings instead of being a continuous layer. This segmentation allows light to pass through the openings, reducing reflectance and improving contrast ratio. The segmented pattern can be implemented using standard photolithography techniques, making the increased complexity manageable through conventional manufacturing processes.
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 configuration increases contrast ratios by minimizing ambient light reflectance and compensates for higher resistance issues, leading to improved light output and image sharpness in LED-based displays.
Implementation Method 1
the patterned bus electrode layer is electrically shorted to the transparent conductive layer and includes higher light absorption materials to reduce reflectance
Data Source
AI summary
A light emitting device includes a backplane, an array of light emitting diodes attached to a front side of the backplane, a dielectric matrix layer located on the front side of the backplane and laterally surrounding the array of light emitting diodes, a transparent conductive layer contacting a front side surface of light emitting diodes within the array of light emitting diodes, and a patterned bus electrode layer electrically shorted to the transparent conductive layer and including an array of openings therein. Each light emitting diode within the array of light emitting diodes is located within an area of a respective opening through the patterned bus electrode layer. The patterned bus electrode layer can include at least one light-absorptive electrically conductive layer providing light absorption. Alternatively or additionally, the patterned bus electrode layer can include a reflective metal layer.