OLED Evaporation Mask with Tapered Positioning Layer
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Solution Overview
Problem
Conventional masks used in OLED production are difficult to accurately control the size and location of small openings, are costly to manufacture, and have a short lifespan, limiting the resolution and accuracy of the organic light emitting layer formation during evaporation processes.
Innovation Solution
A mask comprising a support base with a positioning layer, where the width of the openings in the support base and the through openings in the positioning layer both taper, enhancing tensile strength and evaporation accuracy, and a method for forming this mask involving photoresist layers and etching to achieve precise opening sizes and locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thin mask is used to reduce production cost, then manufacturing cost is reduced, but it becomes difficult to accurately control the size and location of openings and form openings with small size
Solution Approach 1:
The patent applies nesting by placing a positioning layer inside the mask structure. The positioning layer contains through-openings that are smaller than the openings in the mask body, creating a nested configuration where the positioning layer's openings are embedded within the mask's opening pattern. This nested structure enables precise control of deposition patterns while maintaining a cost-effective thin mask body.
Solution Approach 2:
The mask is segmented into two functional parts: a mask body with larger openings and a positioning layer with smaller through-openings. This segmentation allows each layer to serve its specific function - the mask body provides structural support and cost-effectiveness, while the positioning layer delivers high-precision opening control for mini-size features.
2Ease of manufacture
If a thin mask is used, then production cost is reduced, but the mask has a relatively short lifetime
Solution Approach 1:
The positioning layer is nested within the mask body structure, creating a reinforced composite mask. The positioning layer acts as an internal reinforcement that enhances the mechanical strength and durability of the thin mask body, thereby extending mask lifetime while maintaining cost benefits.
Solution Approach 2:
The mask combines two different materials or material configurations - the mask body material and the positioning layer material - to create a composite structure. This composite construction provides both cost-effectiveness and enhanced durability, resolving the contradiction between low cost and long lifetime.
3Manufacturing precision
If openings with mini-size are formed to achieve high resolution, then resolution and control accuracy are improved, but manufacturing complexity and cost increase
Solution Approach 1:
The mask structure is segmented into a simple mask body and a separate positioning layer. This segmentation allows the complex high-precision function to be isolated to the positioning layer, while the mask body remains structurally simple and cost-effective to manufacture.
Solution Approach 2:
The positioning layer acts as a precision template or copy that defines the exact pattern for mini-size openings. By creating this separate positioning layer with precise through-openings, the complex high-resolution pattern can be accurately replicated without complicating the overall mask manufacturing process.
4Ease of manufacture
If a thin mask is used, then production cost is reduced, but it is difficult to form openings with small size
Solution Approach 1:
The positioning layer with small through-openings is nested within the mask body that has larger openings. This nested configuration enables the formation of small-size openings through the positioning layer while the mask body provides structural support and remains cost-effective to manufacture.
Solution Approach 2:
The solution adds a dimensional layer - the positioning layer is placed on one side of the mask body, creating a multi-layered structure. This dimensional addition allows small-size openings to be formed through the positioning layer without requiring the entire mask to be thin, thus maintaining both cost-effectiveness and precision capability.
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 allows for higher accuracy in forming mini-size openings, improving the resolution and extending the working lifetime of the mask, thereby enhancing the evaporation accuracy and reducing production costs.
Implementation Method 1
etching the second surface of the support base to form at least one opening corresponding to the at least one through opening in the positioning layer
Implementation Method 2
at least a portion of the boundary of the through opening is tapered... enhancing tensile strength
Data Source
Figure 1~2
Figure 3
Figure 4(a)~4(b)
AI summary
A mask is disclosed. The mask includes at least one support base having at least one opening formed therein; and at least one positioning layer disposed on the at least one support base, where at least one through opening corresponding to and communicated to the at least one opening, are formed in the at least one positioning layer; and a width of a cross section of each opening in the at least one support base and a width of a cross section of each through openings in the at least one positioning layer reduce gradually from the support base to the positioning layer.