Deposition Mask Contact Control for Uniform Organic EL Patterning
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Solution Overview
Problem
Existing vapor deposition methods struggle to achieve precise and uniform deposition patterns due to gaps between the substrate and the deposition mask, leading to unsharpness and non-uniformity in organic EL display apparatuses.
Innovation Solution
A vapor deposition method and apparatus where the substrate is pressed vertically at the center of deflection of the deposition mask, ensuring substantial contact between the substrate and the mask, thereby eliminating gaps and achieving precise pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the substrate and deposition mask are enlarged to accommodate high definition design and multiple-panel masks, then the screen size and production capacity are improved, but the mask becomes more prone to bowing down at its center, leading to defective pattern layers
Solution Approach 1:
The substrate pressing unit applies preliminary pressing forces to the substrate before vapor deposition begins, pre-compensating for the mask's downward bowing. This preliminary action prevents the formation of gaps between the substrate and mask during deposition, thereby maintaining pattern uniformity despite the large mask size
Solution Approach 2:
The system performs preliminary measurement of the mask's deflection amount and uses this information to determine the appropriate pressing force to be applied by the substrate pressing unit. This preliminary measurement and calculation enable precise control of the substrate-mask contact before the actual deposition process
2Ease of operation
If a flexible plate is used to apply pressure to the substrate, then the substrate can be brought into contact with the mask, but the flexible plate lacks sufficient rigidness to effectively deform the substrate and apply loads
Solution Approach 1:
The substrate pressing unit changes the physical parameters of the pressing mechanism by using adjustable pressing members (such as screws or actuators) that can apply controlled mechanical forces. This allows the system to transition from insufficient flexible plate pressure to adequate substrate deformation and mask contact
Solution Approach 2:
The substrate pressing unit acts as an intermediary mechanism between the pressing force source and the substrate. It includes components such as pressing members, support bases, and measurement devices that mediate the force application process to ensure effective substrate-mask contact
3Manufacturing precision
If multiple plungers are used to apply loads at multiple points, then the contact between substrate and mask is improved, but the exact positions and amounts of loads to be applied are unclear
Solution Approach 1:
The system incorporates measurement devices that detect the actual deflection amount of the mask and provide feedback to the control mechanism. This feedback enables automatic adjustment of the pressing force and position, eliminating the uncertainty about load application while maintaining precision in the deposition pattern
Solution Approach 2:
The substrate pressing unit allows for adjustable pressing positions and forces, enabling the system to adapt to different mask deflection patterns. The pressing members can be positioned and adjusted to apply loads at optimal locations, achieving precise substrate-mask contact without excessive 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
This method allows for the formation of sharp, uniform deposition patterns, enhancing the display quality of organic EL display apparatuses by ensuring effective contact between the substrate and the deposition mask.
Implementation Method 1
When from a vapor deposition source 84 disposed under the mask 81 a vapor deposition material evaporates
Implementation Method 2
a vapor deposition material passes through openings of the mask 81 and is deposited on the substrate 83
Data Source
AI summary
A vapor deposition method and a vapor deposition apparatus that, when a vapor deposition material is deposited on a substrate, make it possible to form deposition layer pattern precisely so that the deposition layer pattern is formed uniformly without a gap formed between a deposition mask and the substrate. A deposition mask is disposed with its periphery held by a frame. A substrate on which a vapor deposition layer is to be formed is mounted over the deposition mask. A vapor deposition source is disposed facing the deposition mask and evaporates a vapor deposition material. The vapor deposition is performed while the substrate is pressed vertically at a position of a center of deflection of the deposition mask and on an upper surface of the substrate until that a length of the substrate substantially becomes identical to a length of the deposition mask being bowed down and expanded.