Stacked Light-Emitting Elements With Asymmetric Sidewall Angles
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Solution Overview
Problem
Existing display devices face challenges in optimizing the efficiency of light-emitting elements, particularly in light-emitting display devices such as OLEDs and micro/nano LED displays, which affect the performance and efficiency of image display.
Innovation Solution
The display device incorporates a design where the first and second light-emitting elements have different sidewall angles, with one being inclined and the other vertical, and are stacked in a specific configuration to enhance light emission efficiency, and includes a common electrode connected to individual light-emitting elements through connection electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If light-emitting elements have uniform sidewall angles for simplified manufacturing, then manufacturing precision is improved, but light emission efficiency deteriorates due to suboptimal light extraction
Solution Approach 1:
The patent applies asymmetry by configuring different sidewall angles for different light-emitting elements within the same display device. Specifically, first light-emitting elements have a first sidewall angle while second light-emitting elements have a second sidewall angle that is different from the first. This asymmetric configuration optimizes light extraction efficiency for each element type, resolving the contradiction between manufacturing simplicity and light emission efficiency.
2Device complexity
If all light-emitting elements have the same sidewall angle, then device complexity is reduced, but light extraction efficiency worsens due to lack of optimization for different emission characteristics
Solution Approach 1:
The patent implements local quality by assigning different sidewall angles to different light-emitting elements based on their specific emission characteristics and positions. The first light-emitting elements have a first sidewall angle optimized for their characteristics, while second light-emitting elements have a second sidewall angle optimized for theirs. This localized optimization improves overall light extraction efficiency without requiring complete structural uniformity across all elements.
3Length of stationary object
If light-emitting elements are stacked in a single layer, then device thickness is reduced, but light emission efficiency deteriorates due to limited light extraction paths
Solution Approach 1:
The patent applies dimensionality change by stacking light-emitting elements in multiple layers vertically. The display device includes first light-emitting elements and second light-emitting elements arranged in different layers, with connection electrodes extending through multiple layers to connect to corresponding elements. This multi-layer vertical arrangement increases light extraction paths and improves light emission efficiency while maintaining a compact overall device thickness.
Data Source
AI summary
A display device includes a lower substrate, a first electrode disposed on the lower substrate, a first light-emitting element disposed on the first electrode, a second electrode disposed on the first light-emitting element, and a second light-emitting element disposed on the second electrode. The first light-emitting element includes a first sidewall and a first bottom surface and the second light-emitting element includes a second sidewall and a second bottom surface. An angle between the first sidewall and the first bottom surface is different from an angle between the second sidewall and the second bottom surface.