Deposition Mask With Inclined Walls For Shadow Prevention
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Solution Overview
Problem
Existing deposition masks for organic EL display devices face challenges in preventing shadow formation during the deposition process, where deposition material moving at an angle to the mask does not reach the substrate effectively due to interference by the mask's structure.
Innovation Solution
A deposition mask design featuring a mask body with through-holes and a support structure, where the support's second through-hole is positioned to overlap the mask body's through-holes, with specific geometric and angular configurations to minimize interference and ensure deposition material reaches the substrate even when moving at angles, enhancing the deposition efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a deposition mask with through-holes is used to form pixels in a desired pattern, then the display device achieves high fineness and proper patterning, but shadow is generated when deposition material moves at an angle to the mask normal, causing incomplete deposition
Solution Approach 1:
The invention transitions from a conventional flat mask structure to a three-dimensional mask body with stepped surfaces and inclined walls. The mask body includes a first surface, a second surface inclined relative to the first surface, and a third surface inclined at a different angle, creating a multi-dimensional geometry that allows deposition material to reach the substrate from multiple angles while maintaining precise patterning through-holes
Solution Approach 2:
The invention employs curved and inclined surfaces instead of flat planes. The mask body features a second surface that is inclined relative to the first surface, and a third surface with specific angular relationships, creating a curved geometric profile that redirects deposition material flow and eliminates shadow regions while preserving the precision of the through-hole pattern
2Ease of manufacture
If the deposition mask has a simple flat structure, then the device complexity is low and manufacturing is easier, but it cannot prevent shadow formation when deposition material moves at an angle
Solution Approach 1:
The mask body is segmented into multiple surfaces (first surface, second surface, third surface) with distinct orientations and functions. Each surface is responsible for directing deposition material from specific angular ranges, and the through-holes are separately formed with precise dimensions. This segmentation allows the complex geometry to be manufactured through systematic processes while achieving superior deposition uniformity
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 effectively prevents shadow formation, ensuring uniform deposition and improved precision in patterning organic materials on substrates, enhancing the quality and consistency of organic EL display devices.
Implementation Method 1
a deposition step in which a deposition mask is brought into contact with the substrate for organic EL so as to deposit an organic material onto the substrate for organic EL is carried out in the deposition apparatus
Data Source
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AI summary
A deposition mask (20) includes: a mask body (30) having two or more first through-holes (35); and a support (40) disposed on the mask body (30) and having a second through-hole (45) located at a position overlapped with the first through-holes (35) in a plan view; wherein: the mask body (30) has a first surface (30a) located on an opposite side of a side of the support (40), and a second surface (30b) located on the side of the support (40); an outermost circumference first through-hole (39), which is located on an outermost circumference in a plan view of the two or more first through-holes (35) located at the position overlapped with the second through-hole (45) in a plan view, includes a first point (P1) which is a center of the outermost circumference first through-hole (39) in a plan view; the second through-hole (45) includes a second point (P2) on an outline (45a) of the second through-hole (45), the second point (P2) being nearest to the first point (P1); the outermost circumference first through-hole (39) has a first wall (39a) which is a wall on a side of the second point (P2), in a first cross-section that is a plane which includes the first point (P1) and the second point (P2) and is parallel to a normal direction (N) of the mask body (30); the outermost circumference first through-hole (39) has a second surface side connection part (39a2) which connects the first wall (39a) and the second surface (30b), in the first cross-section; and the support (40) is located on an opposite side of the first point (P1) side, with respect to a straight line (L1) of straight lines passing the second surface side connection part (39a2) and a given point on the first wall (39a) in the first cross-section, the straight line (L1) having a largest angle with respect to the normal direction (N) of the mask body (30).