Light Shielding Covering for Anode Electrodes in Organic EL Displays
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Solution Overview
Problem
The fabrication process for organic electroluminescence (EL) panel displays introduces defects such as hillocks and spikes in aluminum (Al) wire electrodes, leading to non-uniform luminance and increased power consumption due to voltage drops in larger panels, and the battery effect during the development of anode electrodes reduces reflectance and display performance.
Innovation Solution
A light shielding covering portion made of the same material as the anode electrode is used to cover connection pads and switch elements, preventing the battery effect and maintaining the surface integrity of the anode electrodes during the fabrication sequence, while also reducing wiring resistance by electrically conducting with the wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If aluminum (Al) is used as current supply metal layer to reduce wiring resistance, then wiring resistance is reduced and voltage drop is suppressed, but hillocks and spikes are generated on the wire surface due to heat history in fabrication process
Solution Approach 1:
The patent applies a laminated structure combining aluminum (Al) with heat-resistant high melting point metal to create a composite wire structure. This composite material approach allows the Al core to provide low resistance while the outer heat-resistant metal layer prevents hillock and spike formation during fabrication processes, thus resolving the contradiction between low resistance and surface quality.
Solution Approach 2:
The heat-resistant high melting point metal acts as an intermediary layer between the aluminum core and the external environment during fabrication. This intermediary layer protects the aluminum from direct exposure to heat history that causes surface defects, while still allowing the aluminum to function as the current supply pathway.
2Ease of manufacture
If pad portions are soaked in peeling liquid during fabrication to remove opening defining insulating film, then insulating film is removed effectively, but battery corrosion reaction occurs and surface nature of anode electrodes is deteriorated
Solution Approach 1:
The patent extracts or removes the pad portions from the peeling liquid treatment process by providing a protective covering over the connection pads during the peeling step. This selective protection allows the insulating film to be removed from other areas while preventing battery corrosion reaction on the anode electrode surfaces.
Solution Approach 2:
The light shielding covering portion acts as an intermediary protective layer between the peeling liquid and the connection pads during fabrication. This covering prevents direct contact between the peeling liquid and the metal surfaces, thereby avoiding battery corrosion reaction while still allowing the peeling process to proceed effectively elsewhere.
3Manufacturing precision
If opening defining insulating film is formed by applying photosensitive resin followed by exposure and peeling, then pixel openings are defined, but connection pads are soaked in peeling liquid causing battery effect and reduced reflectance
Solution Approach 1:
The patent extracts the connection pads from the harmful peeling liquid environment by providing a protective covering during the peeling step. This allows the photosensitive resin process to define pixel openings accurately while preventing the connection pads from being soaked in peeling liquid, thus maintaining their reflectance and luminance properties.
Solution Approach 2:
The light shielding covering portion serves as an intermediary protective barrier during the photosensitive resin peeling process. It allows the peeling liquid to effectively remove the opening defining insulating film from pixel areas while preventing contact with connection pads, thereby preserving both the pixel opening definition and the connection pad surface quality.
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 solution effectively prevents the deterioration of anode electrodes, maintains high luminance, and reduces power consumption by minimizing voltage drops and the generation of defects, thereby enhancing the overall display performance and reliability of organic EL panel displays.
Implementation Method 1
a light shielding covering portion shielding the switch elements from light
Implementation Method 2
connection pads provided on the outside of the display region and serving as input portions that provide the wires with a signal
Data Source
AI summary
A display apparatus including: a display region provided with a plurality of pixel portions; wires installed to the respective pixel portions within the display region from an outside of the display region for transmitting a signal to drive the respective pixel portions; connection pads provided on the outside of the display region and serving as input portions to provide the wires with a signal while electrically conducting with the wires; switch elements provided on the outside of the display region in a middle of the wires; and a light shielding covering portion shielding the switch elements from light and formed to cover the connection pads while electrically conducting with the connection pads.