LED Pixel Sidewall Reflector Layout for Forward Display Emission
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Solution Overview
Problem
Conventional vertical light emitting diodes suffer from light shading by electrodes and excessive light leakage at large viewing angles, reducing display quality.
Innovation Solution
The display device incorporates a protruding insulating layer with ohmic contact metal disposed on its side wall to reflect light, reducing light leakage and enhancing forward emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional vertical light emitting diodes are used, then the structure is simple, but light leakage at large viewing angles occurs and forward light emission is insufficient
Solution Approach 1:
The invention converts the harmful light leakage at large viewing angles into beneficial forward light emission by positioning reflective ohmic contact metals on the side walls of protruding insulating structures. The reflected light that would otherwise leak sideways is redirected forward, transforming the harmful scattering effect into enhanced forward illumination.
Solution Approach 2:
The invention introduces a vertical dimension by creating protruding insulating structures with side walls, allowing the ohmic contact metals to be positioned on vertical surfaces rather than only horizontal planes. This dimensional change enables light reflection from multiple angles, directing more light forward while reducing lateral leakage.
2Reliability
If electrodes are placed above light emitting surfaces, then electrical connection is achieved, but light shading occurs reducing display quality
Solution Approach 1:
The invention segments the electrical connection function by separating the light-emitting active area from the electrode structures. The ohmic contact metals are confined to the side walls of protruding insulating structures, leaving the top light-emitting surface free from electrode shading, thus maintaining both electrical connectivity and optical quality.
Solution Approach 2:
The protruding insulating structures serve as intermediaries that carry the ohmic contact metals on their side walls. This intermediary positioning allows electrical connection to be established without the metals directly shading the light-emitting surfaces, as the insulating structures mediate between the electrical and optical requirements.
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 solution improves front viewing angle intensity by 118% to 213% and narrows the half-intensity viewing angle to 55-75 degrees, effectively addressing light shading and leakage issues.
Implementation Method 1
Utilizing the property of high reflectivity of the ohmic contact metal in the visible light band, the light from the light emitting diode is reflected
Data Source
AI summary
Provided is a display device including a substrate and multiple display pixels on the substrate. Each display pixel includes a light emitting unit and an insulating layer. The light emitting unit includes a first ohmic contact metal, a light emitting diode, and a second ohmic contact metal that are disposed in sequence in a direction away from the substrate. The insulating layer is disposed on at least a side of the light emitting diode, and includes a first protruding portion, where a distance between the first protruding portion and the substrate is greater than or equal to a distance between a top surface of the light emitting diode and the substrate. A part of the second ohmic contact metal is disposed on a first side wall of the first protruding portion facing the light emitting diode.