Flat Panel Display Mask with Reinforcing Member and Buffer
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Solution Overview
Problem
Conventional masks for depositing thin films in flat panel displays, such as OLEDs, face issues with mask drooping due to weight, leading to distorted openings and inconsistent electrode patterns, and require improved accuracy and position precision in forming mask patterns.
Innovation Solution
A mask with a reinforcing member and a buffer member is used, where the mask pattern units are supported by the reinforcing member and connected to the buffer member, enhancing robustness and accuracy through the use of materials like Ni-Co alloy and Invar, which provides thermal stability and precise pattern formation via electroforming methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large area metal thin plate mask is used, then the mask can cover the required deposition area, but the mask droops due to its own weight causing distorted openings
Solution Approach 1:
The mask is divided into multiple smaller mask pattern units (112) arranged in a grid pattern, each unit being independently supported by the frame structure. This segmentation prevents the entire large area mask from drooping as a single unit, reducing gravitational deformation and maintaining opening accuracy.
Solution Approach 2:
The frame structure (120) with supporting bars (121, 122) adds a three-dimensional support dimension to the otherwise two-dimensional mask plane. This vertical support structure counteracts the gravitational force causing droop, maintaining the mask's planarity and opening shape accuracy across large areas.
2Stability of the object's composition
If tensile force is applied to prevent mask drooping, then mask stability improves, but the supporting bars curve and openings become distorted
Solution Approach 1:
Instead of applying uniform tensile force across the entire mask, the frame structure provides localized support at specific points through the supporting bars (121, 122). This distributed localized support achieves mask stability without subjecting any single region to excessive stress that would cause bar curvature and opening distortion.
Solution Approach 2:
The mask system combines the thin metal plate mask material with the more rigid frame structure material. This composite construction allows the flexible mask to maintain stability through the rigid frame's geometric strength, avoiding the need for high tensile forces that would deform the supporting bars.
3Strength
If the mask is fixed onto the frame, then the mask is supported, but the openings are distorted due to frame curvature from tensile force
Solution Approach 1:
The frame structure with its geometric configuration of supporting bars acts as a counterbalancing support system that compensates for the gravitational weight of the mask. This counter-support mechanism maintains opening precision without requiring high tensile fixation forces that would cause frame curvature and precision loss.
4Ease of manufacture
If photo process is used to form mask pattern, then the mask can be fabricated, but the accuracy of opening and position accuracy of pixels needs improvement
Solution Approach 1:
The patent replaces the chemical photo etching process with a mechanical precision fabrication method. The mask pattern units are formed using precision mechanical machining or stamping processes that directly create the opening patterns, achieving superior dimensional accuracy and position precision compared to photo process limitations.
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 provides improved robustness, accuracy, and thermal stability, ensuring consistent thin film deposition with reduced distortion and enhanced precision in pattern formation, addressing the issues of mask drooping and pattern inconsistency.
Implementation Method 1
a mask with a reinforcing member and a buffer member, where the mask pattern units are supported by the reinforcing member and connected to the buffer member, enhancing robustness and accuracy through the use of materials like Ni-Co alloy and Invar, which provides thermal stability and precise pattern formation via electroforming methods
Implementation Method 2
Invar, which provides thermal stability
Data Source
AI summary
A mask for depositing a thin film of a flat panel display and a method of fabricating the mask are disclosed. Embodiments of the mask can improve position accuracy and prevent problems caused by thermal expansion of the mask by attaching a reinforcing member and mask pattern units arranged on openings of the reinforcing member using a buffer member. The mask includes a reinforcing member including a plurality of first openings; mask pattern units arranged corresponding to the first openings of the reinforcing member and supported by the reinforcing member; and a buffer member including a plurality of second openings corresponding to the first openings of the reinforcing member, and attaching the reinforcing member to the mask pattern units to support the reinforcing member and the mask pattern units.