Display apparatus having a light-emitting device
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Solution Overview
Problem
Display apparatuses face challenges in maintaining luminance and light-extraction efficiency due to increased viewing angles and power consumption, especially with higher resolutions and more subpixels, as they often suffer from total reflection and reduced light-emitting efficiency.
Innovation Solution
The display apparatus incorporates a planarization layer with protruding portions and grooves, where the light-emitting device's electrodes and light-emitting layer are strategically positioned with an insulating pattern to enhance light extraction by directing light emission at various angles, reducing power consumption and maintaining brightness across wider viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a light-emitting device is disposed on a flat surface of a planarization layer, then the device structure is simple, but light-extraction efficiency is reduced due to total reflection
Solution Approach 1:
The planarization layer is designed with a protruding portion that has a curved upper surface instead of a flat surface. This curvature modifies the angle of light incidence between the first electrode and second electrode, preventing total internal reflection and improving light extraction efficiency while maintaining structural simplicity
Solution Approach 2:
The invention transitions from a two-dimensional flat surface to a three-dimensional protruding structure with height. This dimensional change creates additional light extraction pathways and angles, allowing light to escape more effectively without complicating the overall device manufacturing process
2Measurement precision
If the resolution is increased and more subpixels are used, then the image quality is improved, but power consumption increases
Solution Approach 1:
The curved protruding structure converts what would be wasted light (due to total internal reflection on flat surfaces) into useful emitted light. This improves the efficiency of each subpixel, allowing high-resolution displays to achieve better brightness with lower power consumption per pixel
Solution Approach 2:
By changing the geometric parameters of the planarization layer (creating protrusions with specific heights and curvature radii), the light extraction efficiency is optimized. This allows each subpixel to emit more light effectively, reducing the total power needed to maintain a given brightness level across high-resolution displays
3Ease of manufacture
If the light-emitting device is disposed on a flat surface, then the manufacturing process is simple, but luminance decreases according to an increase in viewing angle
Solution Approach 1:
The curved upper surface of the protruding portion distributes light emission across multiple angles more uniformly. This curvature acts as a natural light diffuser, maintaining luminance consistency across different viewing angles while preserving the simplicity of the manufacturing process
Solution Approach 2:
The vertical protrusion structure adds a height dimension that enables light to be emitted at various angles from the top surface. This three-dimensional configuration naturally broadens the viewing angle and maintains luminance uniformity without requiring complex multi-layer structures or additional manufacturing steps
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
This configuration improves light-extraction efficiency and maintains luminance by directing light emission at various angles, reducing power consumption and enabling higher resolutions without compromising brightness.
Implementation Method 1
light-extraction efficiency can be reduced due to total reflection occurring between the first electrode and the second electrode
Data Source
AI summary
A display apparatus can include a bank insulating layer disposed on a substrate and defining an emission area in a pixel area; a planarization layer between the substrate and the bank insulating layer and including a planarization protruding portion overlapping with the emission area; an insulating pattern disposed on a side surface of the planarization protruding portion and spaced apart from an upper surface of the planarization protruding portion; and a light-emitting device disposed on the planarization layer in the emission area and having a stacked structure including a first electrode, a light-emitting layer and a second electrode. Also, the side surface of the planarization protruding portion has a concave shape that is depressed toward an inside of the planarization protruding portion, and the insulating pattern is disposed between the first electrode and the light-emitting layer of the light-emitting device.