Micro LED Conductive Layer Layout for Uniform Brightness
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Solution Overview
Problem
The resistance value of the semiconductor connection layer in micro light-emitting diode displays is higher than that of a conductor, leading to nonuniform brightness due to varying numbers of recombining electron-hole pairs based on distance from the common ground point.
Innovation Solution
The conductive layer is disposed on the second surface of the connection layer, with a lower resistance value than the connection layer, ensuring even current distribution and uniform brightness across light-emitting mesas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the semiconductor connection layer is used as the common electrode, then the device structure is simplified, but the brightness becomes nonuniform due to high resistance
Solution Approach 1:
An additional conductive layer is introduced as an intermediary between the circuit substrate and the light-emitting mesas. This conductive layer serves as an intermediate electrode that distributes current more uniformly, mediating between the common electrode and the light-emitting structures to resolve the brightness nonuniformity issue while maintaining the simplified device architecture
Solution Approach 2:
The electrode structure is segmented into multiple functional layers: the semiconductor connection layer serving as the common electrode and an additional conductive layer positioned between the circuit substrate and the light-emitting mesas. This segmentation allows each layer to perform its specific function optimally, with the conductive layer specifically addressing current distribution uniformity
2Illumination intensity
If the conductive layer is disposed on the first surface of the connection layer, then the current distribution is improved, but the manufacturing yield decreases
Solution Approach 1:
Instead of placing the conductive layer on the first surface of the connection layer (conventional approach), the invention inverts the positioning by placing the conductive layer on the second surface of the connection layer. This inversion resolves the manufacturing yield issue while still achieving uniform current distribution through the connection layer to the light-emitting mesas
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 achieves uniform brightness and improved yield by evenly distributing current, regardless of the distance from the common ground point, enhancing the display's performance.
Implementation Method 1
the resistance value of the conductive layer is less than the resistance value of the connection layer, the current of the circuit substrate may be transmitted more evenly through the conductive layer
Implementation Method 2
the same potential difference may drive the same number of recombining electron-hole pairs, which may prevent the micro light-emitting diode display device from having nonuniform brightness
Data Source
AI summary
A micro light-emitting diode display device including a circuit substrate, an epitaxy structure and a conducting layer is provided. The epitaxy structure is electrically connected to the circuit substrate, and includes a connection layer and a plurality of light-emitting mesas. The plurality of light-emitting mesas are disposed on the connection layer, wherein a thickness of the connection layer is less than a thickness of the plurality of light-emitting mesas, and the connection layer has a first surface exposed by the plurality of light-emitting mesas and a second surface opposite to the first surface. The conducting layer is disposed on the second surface of the connection layer and exposes a plurality of sub-areas of the second surface, wherein a vertical projection of the conductive layer onto the connection layer overlaps a vertical projection of the first surface onto the connection layer.