Dual Mask Alignment for Uniform OLED Organic Layer Deposition
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Solution Overview
Problem
Existing methods for forming organic light emitting layers in OLED displays often result in non-uniform thickness, leading to inconsistent brightness across pixel areas due to the lack of precise control over the application of organic materials.
Innovation Solution
An apparatus and method utilizing a stage, first and second masks, and an inkjet head unit, where the second mask is movable to align with the first mask, allowing for simultaneous and uniform application of organic material to pixel areas through a magnetic force-driven alignment system, ensuring consistent thickness of the organic light emitting layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to form organic light emitting layers, then the formation process is simple, but the thickness uniformity is poor leading to inconsistent brightness
Solution Approach 1:
The apparatus divides the single mask into two separate masks (first mask and second mask). The first mask has first openings corresponding to pixel areas, and the second mask has second openings that can be positioned to overlap with the first openings. This segmentation allows for more precise control of material deposition and better thickness uniformity while maintaining manageable complexity through modular design
Solution Approach 2:
The second mask acts as an intermediary component between the inkjet head unit and the substrate. It temporarily holds the organic material in its second openings, then transfers it through the first openings to the pixel areas. This intermediary mechanism enables precise material distribution and uniform thickness control without requiring direct complex positioning between the inkjet head and substrate
2Manufacturing precision
If material is applied directly to pixel areas, then the process is fast, but the material distribution is non-uniform
Solution Approach 1:
The apparatus performs preliminary action by first supplying organic material to the second openings of the second mask, then later transferring it to the substrate through the first openings. This two-stage process ensures uniform material distribution in the masks before deposition, achieving both uniformity and efficiency
Solution Approach 2:
The second mask automatically transfers the organic material from its second openings to the first openings of the first mask through relative movement. This self-service mechanism eliminates the need for complex external positioning systems, maintaining high productivity while achieving uniform material distribution
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 enables the formation of organic light emitting layers with uniform thickness, enhancing the consistency and brightness of OLED displays by ensuring precise and uniform material distribution across pixel areas.
Implementation Method 1
an electromagnetic unit configured to generate a magnetic force in response to a source voltage applied thereto. The apparatus is configured to hold the intermediate product between the stage and the first mask, configured to make the first mask in contact with the pixel defining layer by the magnetic force of the electromagnetic unit, and further configured to make the second mask in contact with the first mask by the magnetic force of the electromagnetic unit
Implementation Method 2
an inkjet head unit disposed over the second mask and configured to substantially simultaneously supply an organic material to the third openings when the second mask is in the first position
Data Source
AI summary
An organic light-emitting layer forming apparatus includes a stage supporting an intermediate product of an organic light emitting device, which includes a substrate, and a pixel defining layer including first openings. The apparatus includes a first mask disposed over the stage and including second openings, and a second mask disposed over the first mask and including third openings. The second mask is movable relative to the first mask between first and second positions. The third openings do not overlap the second openings in the first position while overlapping the second openings in the second position. The apparatus includes an inkjet head unit disposed over the second mask and supplying an organic material to the third openings of the second mask in the first position. The second mask moves to the second position to transfer the organic material through the second openings.