Tiled Display Electrode Height Compensation for Uniform Sub-Pixel Emission
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Solution Overview
Problem
Inorganic light emitting diodes suffer from image quality deterioration when driven using methods optimized for organic light emitting diodes, due to variations in light wavelength with driving current, leading to mounting defects and reduced display quality.
Innovation Solution
A display device design featuring a substrate with sub-pixels, active layers, and metal layers, including a height difference compensation mechanism with correction holes and dummy pattern layers, allows for flip chip type light emitting elements with optimized electrode placement to maintain consistent light emission and improve yield and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If inorganic light emitting diodes are driven using methods optimized for organic light emitting diodes, then the driving method is simple and compatible, but the light wavelength varies with driving current causing image quality deterioration
Solution Approach 1:
The patent applies different driving methods to different regions (sub-pixels) by controlling driving currents independently through separate electrodes (anode and cathode electrodes with different potentials). This allows each sub-pixel to be driven optimally while maintaining overall system compatibility, resolving the contradiction between simple driving method compatibility and image quality precision.
2Device complexity
If the electrode structure is simplified, then the device complexity is reduced, but mounting defects occur due to height differences between electrodes
Solution Approach 1:
The patent introduces a height dimension to resolve the mounting defect problem. By forming the anode electrode at a first height and the cathode electrode at a second height (different heights), the patent compensates for height differences caused by planarization layers, enabling reliable flip-chip mounting of light emitting elements while maintaining a relatively simple overall electrode structure.
3Reliability
If planarization layers are added to compensate height differences, then mounting reliability improves, but the device complexity and manufacturing steps increase
Solution Approach 1:
The patent performs preliminary height compensation by forming the anode electrode at a different height than the cathode electrode before mounting the light emitting elements. This preliminary action (creating height difference through selective layer formation) eliminates the need for additional planarization layers that would otherwise be required, thereby improving mounting reliability while avoiding increased 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 solution effectively alleviates mounting defects and enhances display quality by maintaining consistent light emission across sub-pixels, regardless of driving current variations, thereby improving the reliability and efficiency of the display device.
Implementation Method 1
a light emitting element disposed on each of the plurality anode electrodes and the cathode electrode
Data Source
AI summary
A display device includes a substrate including a display area in which a plurality of sub-pixels are disposed, a plurality of anode electrodes respectively connected to the plurality of sub-pixels, and a cathode electrode connected to the plurality of sub-pixels and spaced apart from each of the plurality of anode electrodes. Each of the plurality of anode electrodes is disposed closer to the substrate than the cathode electrode by a height difference compensation part.