Nanowire LED Pixel Structure for Perpendicular Light Extraction
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Solution Overview
Problem
The efficiency of light extraction from nanowire LEDs in display devices is compromised due to the peak of light intensity being inclined relative to the direction perpendicular to the semiconductor substrate.
Innovation Solution
A display device design featuring a substrate with a plurality of pixels, each equipped with inorganic light emitting elements. These elements include a semiconductor substrate with a convex second face and semiconductor nanowires extending perpendicular to the first face, optimizing light emission and extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If nanowire LEDs are used for display devices, then the light emission intensity is enhanced, but the light extraction efficiency decreases due to the peak of light intensity being inclined relative to the direction perpendicular to the semiconductor substrate
Solution Approach 1:
The patent introduces a microlens structure that adds a new dimensional element (curved surface geometry) to redirect light rays. The microlens transforms the inclined light emission from the nanowire LED by refracting rays at different angles, converting oblique emission into perpendicular emission relative to the substrate, thereby resolving the directional mismatch problem
Solution Approach 2:
The microlens acts as an intermediary optical element positioned between the nanowire LED and the external environment. It mediates the light transmission by receiving inclined light rays from the nanowire and redirecting them perpendicular to the substrate, thus serving as a bridge that converts the unfavorable emission angle into a favorable extraction direction
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 design enhances light extraction efficiency by aligning the light emission direction with the substrate, reducing light diffusing towards the central part and improving overall display performance.
Implementation Method 1
The light emitting diodes are coupled to an array substrate (a driver back plane in JP-A-2017-529557), in which the array substrate includes a pixel circuit for driving the light emitting diodes
Implementation Method 2
The nanowire LED has a peak of light intensity in a direction inclined with respect to a direction perpendicular to the semiconductor substrate
Implementation Method 3
a semiconductor substrate having a first face facing the substrate and a second face provided in a convex shape on a side opposite from the first face
Data Source
AI summary
A display device includes a substrate; a plurality of pixels provided on the substrate; and a plurality of inorganic light emitting elements provided on each of the pixels. The inorganic light emitting elements each include a semiconductor substrate having a first face facing the substrate and a second face provided in a convex shape on a side opposite from the first face; and a plurality of semiconductor nanowires provided on the first face, the semiconductor nanowires extending in a direction perpendicular to the first face.