LED Current Spreading Layer with Reverse Trapezoidal Concave
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Solution Overview
Problem
Conventional light emitting diode (LED) structures face challenges in uniformly distributing current without affecting light intensity, leading to either reduced luminous efficiency or increased thermal concentration due to non-uniform current spreading and light shading issues.
Innovation Solution
A light emitting diode structure featuring a substrate, semiconductor layers, a current resisting layer, a current spreading layer with a reverse trapezoidal concave design, and electrodes, where the current spreading layer is formed with a P-type semiconductor and the current resisting layer with an N-type semiconductor, allowing for uniform current distribution and reduced light shading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the areas of the electrodes are increased to uniformly spread current, then the current distribution is improved, but the light-shading area is increased and luminous efficiency deteriorates
Solution Approach 1:
The current spreading layer is designed with non-uniform thickness, being thicker at the edges and thinner at the center. This local variation in thickness creates different electrical resistance characteristics in different regions, enabling uniform current distribution without requiring larger electrode areas. The local quality change resolves the contradiction by achieving current uniformity through spatially varying material properties rather than increasing overall electrode size.
Solution Approach 2:
The patent changes the thickness parameter of the current spreading layer to control current distribution. By adjusting the thickness from center to edge, the electrical resistance is modified locally, allowing current to spread uniformly across the active layer. This parameter change enables achieving uniform current distribution while maintaining small electrode areas, thus preserving luminous efficiency.
2Loss of energy
If the light-shading area of the electrodes is reduced to increase luminous efficiency, then the luminous efficiency is improved, but the current is crowded and cannot be spread uniformly and thermal concentration is worsened
Solution Approach 1:
The current spreading layer exhibits local quality variation with different thicknesses at different locations. The thicker edges provide lower resistance paths for current flow, while the thinner center provides higher resistance. This local quality differentiation enables uniform current distribution even with reduced electrode areas, resolving the contradiction between luminous efficiency and current uniformity.
3Device complexity
If a conventional planar electrode structure is used, then the structure is simple, but current crowding occurs and light flux at oblique angles is reduced
Solution Approach 1:
The current spreading layer extends in the vertical dimension with varying thickness, transforming the conventional two-dimensional planar electrode into a three-dimensional structure. This dimensional change allows the electrode to achieve both current spreading function and light extraction function, enabling uniform current distribution and enhanced oblique light emission without significantly increasing overall device complexity.
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 structure enhances luminous efficiency by uniformly spreading current, reducing the current crowding effect and increasing light flux emitted at oblique angles, thereby improving the overall performance of the LED without compromising light intensity.
Implementation Method 1
The current spreading layer covers the second semiconductor layer and the current resisting layer... allowing for uniform current distribution
Implementation Method 2
The light-emitting diode (LED) emits a light by converting electric energy into photo energy... When a voltage is applied to a positive polarity and a negative polarity of an LED chip, the electrons and the holes will be combined and then emit energy in a form of light
Data Source
AI summary
A light emitting diode structure comprising a substrate, a first semiconductor layer, an active layer, a second semiconductor layer, a current resisting layer, a current spreading layer, a first electrode and a second electrode is provided. The first semiconductor layer is formed on the substrate. The active layer covers a portion of the first semiconductor layer, and exposes another portion of the first semiconductor layer. The second semiconductor layer is formed on the active layer. The current resisting layer covers a portion of the second semiconductor layer, and exposes another portion of the second semiconductor layer. The current spreading layer covers the second semiconductor layer and the current resisting layer. The current spreading layer is formed with a reverse trapezoidal concave over the current resisting layer. The first electrode is disposed on the first semiconductor layer. The second electrode is disposed within the reverse trapezoidal concave.