Hybrid Stick Mask Assembly for OLED Deposition Alignment
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Solution Overview
Problem
Existing stick masks face challenges in achieving precise high-resolution deposition patterns due to sagging and misalignment issues, particularly in large-area OLED displays, limiting their ability to produce high-definition images and requiring frequent replacements, which affect manufacturing efficiency and precision.
Innovation Solution
A hybrid stick mask is introduced, comprising a structural stick mask and cell-unit masks with distinct thicknesses, thermal expansion coefficients, and reinforcing bands to maintain tension and alignment, allowing for precise high-resolution deposition patterns and reducing shadow effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the mask thickness is reduced to 5 μm to 30 μm for high-resolution deposition, then the pixel size decreases and shadow effects are prevented, but the mask sags in gravitational direction and hole position alignment becomes imprecise
Solution Approach 1:
The mask is divided into multiple independent stick masks, each with its own tension-fixing portions. This segmentation allows each stick mask to be individually tensioned and maintained flat, preventing sagging while enabling high-resolution deposition through thin mask structure (5-30 μm).
Solution Approach 2:
The mask thickness parameter is changed to 5-30 μm to achieve high-resolution deposition patterns and prevent shadow effects. Concurrently, tension-fixing portions are added to compensate for the reduced structural stability, maintaining mask flatness despite the thin profile.
2Manufacturing precision
If the mask is tensioned and tightly pulled to maintain flatness with TFT glass, then the mask stays pressed against the glass without gaps, but additional wings and clamps are required increasing device complexity
Solution Approach 1:
The tension-fixing portions are integrated directly into the stick mask structure, merging the mask body and tensioning elements into a single component. This eliminates the need for separate wings and clamps, reducing device complexity while maintaining mask flatness and alignment precision.
Solution Approach 2:
The stick mask structure includes built-in tension-fixing portions that enable self-tensioning and self-maintaining of flatness. The mask automatically stays pressed against the TFT glass without requiring external clamping mechanisms, simplifying the overall device structure.
3Productivity
If multiple stick masks are used for large-area displays, then mass production of large-area OLEDs is enabled, but interference between adjacent masks affects deposition precision
Solution Approach 1:
The large-area mask system is segmented into multiple independent stick masks with defined spacing relationships. Each stick mask maintains its own tension and flatness independently, preventing interference between adjacent masks while enabling mass production of large-area OLED displays through coordinated operation.
4Manufacturing precision
If the mask is made thin to decrease pixel size for high resolution, then shadow effects are prevented, but the mask becomes difficult to embody with current commercialized techniques
Solution Approach 1:
The mask thickness parameter is set to 5-30 μm to achieve high-resolution pixel definition and prevent shadow effects. The invention provides a fabrication method using sequential deposition processes that makes producing such thin masks with precise hole patterns feasible with current commercialized techniques.
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 hybrid stick mask enhances manufacturing precision, reduces shadowing, and facilitates easy maintenance by minimizing interference between masks, enabling the production of large-area high-resolution OLED displays with improved productivity and reliability.
Implementation Method 1
heating an organic material in a deposition source located at a lower portion of a chamber and vaporizing the heated organic material to allow the organic material to pass through a mask and be deposited on TFT glass
Implementation Method 2
it is necessary to apply tension to and tightly pull the mask to maintain an elastic force
Implementation Method 3
apply tension to and tightly pull the mask to maintain an elastic force
Implementation Method 4
parts of the edges of the mask which are overlapped with a frame are welded to manufacture a mask assembly
Data Source
AI summary
Disclosed are a hybrid stick mask and a manufacturing method therefor, a mask assembly including a hybrid stick mask, and an organic light emitting display device using same. A hybrid stick mask, according to one embodiment of the present invention, comprises: a structural stick mask having a plurality of openings in a first direction, having first bonding regions provided along the circumference of the openings, and having tension fixing portions at both ends in the first direction so as to be fixed to a frame while tensile force is applied; and cell unit masks each having a deposition region corresponding to the opening, and a second bonding region provided along the circumference of the deposition region so as to be bonded to the first bonding region. Each of the cell unit masks can be individually coupled to the structural stick mask.