Maskless Evaporation for High-Definition Display Pixel Electrodes
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Solution Overview
Problem
The manufacturing of high-definition display apparatuses using organic EL devices faces challenges due to inaccuracies in forming island-shaped light-emitting layers with existing vacuum evaporation methods, leading to deviations in shape and position, reduced aperture ratio, and increased manufacturing costs.
Innovation Solution
A method involving the formation of insulating and conductive layers, sacrificial layers, and processing techniques to create island-shaped light-emitting devices without the need for metal masks, allowing for precise control of pixel electrodes and high-definition display capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If vacuum evaporation method using metal mask is used to form island-shaped light-emitting layers, then light-emitting layers can be formed, but dimensional accuracy and position precision are poor due to mask deviation and vapor scattering
Solution Approach 1:
The invention extracts and removes the metal mask from the vacuum evaporation system, transitioning to a maskless deposition approach. This eliminates the source of dimensional inaccuracies (mask positioning errors, warping, and vapor scattering off the mask) while maintaining the ability to form precise island-shaped light-emitting layers through direct digital patterning or other maskless methods
Solution Approach 2:
The invention replaces the mechanical metal mask system with a digital or field-based patterning approach. Instead of using physical masks that require precise mechanical positioning, the system uses electronic control to define the deposition pattern, thereby eliminating mechanical errors and improving dimensional accuracy
2Area of stationary object
If metal mask is used for forming light-emitting layers, then light-emitting layers can be patterned, but aperture ratio is reduced due to outline blurring and thickness variation
Solution Approach 1:
By removing the metal mask from the system, the invention eliminates the vapor scattering effect that causes outline blurring and thickness variation. The maskless deposition approach allows vapor to deposit directly onto the substrate without interacting with mask edges, resulting in sharper outlines and more uniform thickness across the light-emitting layer
Solution Approach 2:
The invention applies preliminary protective measures by forming sidewalls before completing the light-emitting layer deposition. These sidewalls prevent vapor scattering and maintain precise geometric definitions during the deposition process, ensuring uniform thickness and sharp outlines that maximize aperture ratio
3Reliability
If vacuum evaporation method with metal mask is used, then light-emitting layers can be formed, but manufacturing yield is reduced due to heat deformation and low mask accuracy in large-size displays
Solution Approach 1:
The invention extracts the metal mask from the manufacturing process, eliminating the primary source of heat-related deformation and positioning errors. Without the mask absorbing and redistributing heat, thermal deformation is minimized, and without mask positioning errors, dimensional accuracy is improved, thereby increasing manufacturing yield for large-size displays
Solution Approach 2:
The invention replaces the mechanical mask-based system with a maskless deposition system that is less sensitive to thermal effects and positioning errors. This substitution simplifies the manufacturing process by removing the mask handling, positioning, and cooling requirements, thereby improving yield while reducing overall process complexity
4Quantity of substance
If metal mask is used for manufacturing display apparatus, then light-emitting layers can be formed, but initial investment and manufacturing cost increase due to need for multiple equipment lines
Solution Approach 1:
The invention extracts the metal mask from the manufacturing system, enabling a single vacuum evaporation equipment line to perform all light-emitting layer depositions without requiring parallel equipment lines for mask maintenance. This eliminates the need for duplicate equipment, thereby reducing initial investment while maintaining full production capacity
Solution Approach 2:
The maskless deposition approach enables continuous manufacturing operations without interruption for mask cleaning or replacement. A single equipment line can operate continuously without the downtime required for mask maintenance, maintaining full production capacity while reducing the need for redundant equipment lines
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
This approach enables the production of high-definition display apparatuses with improved aperture ratio, reduced manufacturing costs, and increased reliability by eliminating the need for metal masks and simplifying the manufacturing process.
Implementation Method 1
an island-shaped light-emitting layer can be formed by a vacuum evaporation method using a metal mask
Data Source
AI summary
A high-definition and high-resolution display apparatus is provided. A conductive film, a first layer, and a first sacrificial layer are formed. The first layer and the first sacrificial layer are processed to expose part of the conductive film. A second layer and a second sacrificial layer are formed over the first sacrificial layer and the conductive film. The second layer and the second sacrificial layer are processed to expose part of the conductive film. The conductive film is processed to form a first pixel electrode overlapping with the first sacrificial layer and a second pixel electrode overlapping with the second sacrificial layer. Two insulating films covering at least a side surface of the first pixel electrode, a side surface of the second pixel electrode, a side surface of the first layer, a side surface of the second layer, a side surface and a top surface of the first sacrificial layer, and a side surface and atop surface of the second sacrificial layer are formed. The two insulating films are processed to form a sidewall covering at least the side surface of the first pixel electrode and the side surface of the first layer. The first sacrificial layer and the second sacrificial layer are removed. A common electrode is formed over the first layer and the second layer.