Laser Irradiation Device with Variable Mask for OLED Transfer
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Solution Overview
Problem
The existing Laser-Induced Thermal Imaging (LITI) method for fabricating organic light-emitting display devices (OLEDs) faces challenges in achieving uniform transfer layer patterns and maximizing transfer efficiency, leading to defects like edge open defects and thermal damage, which affect emission efficiency and lifespan.
Innovation Solution
A laser irradiation device with a mask having light transmitting portions of varying lengths and regions, allowing for differential energy distribution along the mask, is used to control the laser beam dose and pattern, ensuring uniform energy application and minimizing heat damage during the LITI process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional mask with uniform light transmitting portions is used in LITI method, then the manufacturing process is simple, but the transfer layer pattern quality deteriorates and edge open defects occur
Solution Approach 1:
The mask is designed with light transmitting portions having different first lengths along the second axis, creating local variations in laser energy transmission. This allows different regions of the mask to provide different energy doses, preventing edge open defects and improving transfer layer pattern quality by addressing specific local requirements rather than using a uniform design throughout.
Solution Approach 2:
The mask structure is segmented into multiple light transmitting portions with varying first lengths along the second axis. This segmentation allows independent optimization of energy distribution in different regions, enabling precise control over laser irradiation patterns to eliminate defects while maintaining manufacturing feasibility.
2Productivity
If excessive laser energy is applied to maximize transfer efficiency, then transfer speed improves, but thermal damage occurs to the organic layer
Solution Approach 1:
The mask design varies the first length of light transmitting portions along the second axis, creating spatial parameter changes in laser energy transmission. This allows optimization of energy distribution across different regions, achieving sufficient transfer efficiency in areas needing it while limiting energy exposure in sensitive areas to prevent thermal damage.
Solution Approach 2:
Different regions of the mask provide different levels of laser energy transmission based on the specific requirements of underlying structures. This local quality approach ensures that energy is distributed precisely where needed for efficient transfer while protecting vulnerable areas from excessive heat that would cause damage.
3Manufacturing precision
If uniform laser energy distribution is used across the mask, then the device structure is simple, but edge open defects occur in the transfer layer pattern
Solution Approach 1:
The mask incorporates light transmitting portions with varying first lengths along the second axis to provide localized energy enhancement at edges and corners where open defects are prone to occur. This targeted energy distribution improves edge quality and pattern completeness without requiring complete redesign of the entire mask structure.
Solution Approach 2:
The mask is divided into multiple light transmitting portions with different dimensional characteristics along the second axis, allowing segmented control of laser energy distribution. This segmentation enables precise targeting of edge regions to prevent open defects while maintaining simplicity in overall mask design.
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 enhances the quality of the transfer layer pattern, prevents edge open defects, and maximizes emission efficiency by applying the right dose of laser energy to the donor substrate, thereby improving the overall efficiency and longevity of the OLEDs.
Implementation Method 1
a light-to-heat conversion layer, and a transferable layer on the donor substrate. The transferable layer is released from the donor substrate and adhered to the acceptor substrate by the LITI method
Implementation Method 2
irradiating a laser beam through the mask onto a surface of the donor device. The transferable layer receives energy from the laser beam, and wherein the amount of energy varies in the portion along the second axis
Data Source
AI summary
A laser irradiation device and a method of fabricating an organic light emitting display device (OLED) using the same are disclosed. The laser irradiation device includes: a laser source generating a laser beam; a mask disposed below the laser source and patterning the beam and a projection lens disposed below the mask and determining magnification of the laser beam through the mask, wherein the laser beam penetrating the mask has different doses in at least two regions. Thus, the laser irradiation device can maximize emission efficiency and enhance the quality of a transfer layer pattern when an organic layer of the OLED is formed using the laser irradiation device.