Light Emitting Element Current Density Uniformity
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Solution Overview
Problem
Existing light emitting elements experience uneven light emission intensity distribution due to variations in current density caused by electrode disposition, leading to suboptimal light extraction and emission efficiency.
Innovation Solution
A light emitting element design featuring a light-transmissive substrate with semiconductor stacked-layer bodies having n-type and p-type semiconductor layers, holes, and electrodes that allow for balanced current distribution across the emitting surface, with external connection electrodes configured to connect these layers for improved current flow and light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional electrode disposition is used with a single semiconductor layer, then the device structure is simple, but the current density becomes uneven leading to poor light emission distribution
Solution Approach 1:
The semiconductor layer is divided into multiple stacked layers (first semiconductor layer, second semiconductor layer, third semiconductor layer) with different hole concentrations. This segmentation allows independent optimization of current distribution and light emission characteristics in each layer, resolving the contradiction between simple structure and uniform light emission.
Solution Approach 2:
Different regions of the semiconductor structure are assigned different properties: the first semiconductor layer has higher hole concentration for efficient light emission, while the second and third layers have lower hole concentrations to facilitate current distribution. This local differentiation enables both uniform current density and high light emission intensity.
2Area of stationary object
If the distance between anode and cathode electrodes is reduced, then the device size is minimized, but the current density becomes highly concentrated causing uneven light emission
Solution Approach 1:
The patent introduces a vertical stacking dimension with multiple semiconductor layers at different heights. This three-dimensional arrangement allows current to distribute through multiple pathways in the vertical direction, reducing horizontal current concentration and enabling uniform light emission even in a compact device footprint.
Solution Approach 2:
The electrode structure is segmented into multiple contact regions corresponding to different semiconductor layers. The anode electrode contacts the first semiconductor layer while the cathode electrode contacts the second and third layers, creating distributed current injection points that prevent current concentration and maintain emission uniformity.
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 reduces unevenness in current density, resulting in enhanced light emission intensity distribution and improved light extraction efficiency across the light emitting device.
Implementation Method 1
a first semiconductor stacked-layer body having a first n-type semiconductor layer provided above part of the light-transmissive substrate, and a first p-type semiconductor layer provided above the first n-type semiconductor layer
Data Source
AI summary
Provided are a light emitting element and a light emitting device with improved light emission intensity distribution. A light emitting element includes a light-transmissive substrate, an n-type semiconductor layer, a first p-type semiconductor layer, a first p-side electrode, a first n-side electrode, a second p-type semiconductor layer, a second p-side electrode, and a second n-side electrode. A light emitting device includes the light emitting element, and an external connection electrode provided at the light emitting element on a side opposite to the light-transmissive substrate. The external connection electrode includes an n-side external connection electrode connected to the first n-side electrode and the second n-side electrode, a first p-side external connection electrode connected to the first p-side electrode, and a second p-side external connection electrode connected to the second p-side electrode.