Electrostatic Mask Support for Precise Large-Area Deposition
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Solution Overview
Problem
The sagging of masks during the deposition process in large substrates leads to reduced deposition precision in organic light emitting diode manufacturing, particularly in organic light emitting display devices, due to the increased size of the mask causing distortion.
Innovation Solution
A deposition apparatus with a grid member supported by electrostatic force, utilizing a voltage generator to apply opposing polarities to the grid member and mask, and a mask with conductive base substrate and insulating film to prevent sagging and ensure precise deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the mask size is increased to match larger substrates, then the deposition area is improved, but mask sagging occurs reducing deposition precision
Solution Approach 1:
The patent applies electrostatic force as a counteracting force to gravity-induced mask sagging. By applying opposite polarity voltages to the grid member and mask, an electrostatic attraction force is generated that counterbalances the gravitational force causing the mask to sag, thereby maintaining mask position and deposition precision despite increased mask area.
Solution Approach 2:
The patent changes the physical state and electrical properties of the mask system by applying voltage. The mask and grid member are transformed from a passive mechanical structure to an actively controlled electrostatic system, where electrical parameters (voltage polarity and magnitude) are adjusted to prevent sagging and maintain deposition precision across large substrate areas.
2Area of stationary object
If the mask size is increased to cover larger substrates, then the substrate coverage is improved, but mask distortion increases
Solution Approach 1:
The electrostatic force generated between the grid member and mask acts as a counterbalancing force that prevents gravitational distortion of the mask. This allows the mask to maintain its intended shape and structural integrity even when scaled up to cover larger substrate areas, eliminating the trade-off between coverage area and shape stability.
Solution Approach 2:
The patent employs a composite structure consisting of the mask, insulating film, and grid member working together as an integrated electrostatic system. This composite structure combines mechanical support (mask), electrical insulation (insulating film), and electrostatic actuation (grid member) to achieve both large substrate coverage and maintained shape stability.
3Manufacturing precision
If electrostatic force is applied to prevent mask sagging, then deposition precision is improved, but device complexity increases
Solution Approach 1:
The grid member serves multiple functions: it provides mechanical support structure, acts as an electrostatic actuator to prevent mask sagging, and defines the deposition pattern through its opening structure. By combining these functions into a single component, the patent reduces overall device complexity while achieving improved deposition precision through electrostatic force application.
Solution Approach 2:
The patent merges the mask support structure with the electrostatic actuation system by integrating the grid member that serves both as a mechanical framework and an electrical component. This consolidation eliminates the need for separate support and actuation systems, reducing device complexity while maintaining deposition precision.
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 apparatus effectively prevents mask sagging, ensuring accurate and reliable deposition on the substrate by maintaining the mask's position, thereby improving the precision and reliability of the deposition process.
Implementation Method 1
a voltage generator that applies a voltage; a grid member that is electrically connected to the voltage generator... a mask that is disposed on the grid member and is electrically connected to the voltage generator... opposing voltages are applied to the grid member and the mask to generate a monopolar electrostatic force
Data Source
AI summary
A deposition apparatus includes: a voltage generator including a first contact portion configured to apply a first voltage and a second contact portion configured to apply a second voltage having an opposite polarity to the first voltage; a grid member having conductivity, electrically connected to the first contact portion, and defining first openings therein; and a mask disposed on the grid member, electrically connected to the second contact portion, and including a base substrate defining second openings therein, and an insulating film surrounding the base substrate and defining third openings therein on a top surface of the base substrate and fourth openings therein on a bottom surface of the base substrate.