OLED Pixel Defining Layer Spherical Spacer Fabrication
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Solution Overview
Problem
Conventional OLED display device fabrication methods require an additional photolithography process to form a spacer pattern, which incurs extra material costs and can result in residual spacer film layers on the first electrode, and are prone to damage from uneven deposition masks.
Innovation Solution
The use of spherical spacers applied to the pixel defining layer, which are fixed using a bake process, eliminates the need for a photolithography process to form a spacer pattern and prevents damage from deposition mask unevenness, allowing for the formation of an organic layer with an emission layer (EML) without shadow phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional photolithography process is used to form a spacer pattern, then the pixel defining layer is protected from deposition mask damage, but additional material costs are incurred and residual spacer film remains on the first electrode
Solution Approach 1:
The invention extracts and removes the harmful photolithography process from the fabrication sequence. Instead of forming a continuous spacer pattern through photolithography, the method directly deposits the organic layer while the pixel defining layer's structural features (openings and non-openings) naturally provide the necessary spacing function, eliminating residual film issues and material waste
Solution Approach 2:
The invention converts the potential harm of direct deposition mask contact into a benefit by utilizing the pixel defining layer's existing topography. The openings and non-openings regions create natural spacing that protects against mask damage without requiring additional protective layers, turning a vulnerable surface into a self-protecting structure
2Manufacturing precision
If the deposition mask is closely adhered to the target to prevent inconsistencies, then deposition precision is improved, but the pixel defining layer is scratched from mask unevenness
Solution Approach 1:
The invention applies local quality by utilizing different regions of the pixel defining layer (openings vs. non-openings) to provide different functions. The non-opening regions provide spacing and protection where needed, while opening regions allow direct deposition, creating a locally optimized structure that simultaneously achieves precision and protection
Solution Approach 2:
The pixel defining layer is prepared in advance with its opening/non-opening pattern before deposition begins. This preliminary structuring creates built-in spacing that prevents mask contact damage before the deposition process starts, eliminating the need for runtime protection mechanisms
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 approach reduces material costs, prevents residual spacer film degradation, and ensures uniform organic layer formation by maintaining spherical spacers only on specific regions, thereby enhancing the fabrication process efficiency and reducing damage to the pixel defining layer.
Implementation Method 1
spherical spacers applied to the pixel defining layer, which are fixed using a bake process
Implementation Method 2
a material contained in the crucible 3 is then deposited on the target 5
Data Source
AI summary
An organic light emitting diode (OLED) display device and a method of fabricating the same are provided. When an organic layer having an emission layer (EML) is formed using a deposition mask, damage to a pixel defining layer due to inconsistencies or unevenness of the deposition mask is prevented or reduced using spherical spacers disposed on the pixel defining layer. A plurality of spherical spacers are applied on the pixel defining layer prior to forming an opening in the pixel defining layer exposing the first electrode. An organic layer having an emission layer (EML) is formed on the first electrode at the opening by using a deposition mask. The spherical spacers prevent or reduce damage to the pixel defining layer caused by inconsistencies or unevenness in the deposition mask by maintaining a spacing between the pixel defining layer and the deposition mask.