Auxiliary Wiring Formation in Microdisplay Devices
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Solution Overview
Problem
In organic electroluminescence (EL) display devices for microdisplays, forming auxiliary wiring on transparent electrodes with high accuracy is challenging due to the difficulty in creating insulating layers that isolate light-emitting layers from contacts, leading to increased sheet resistance and reduced image quality.
Innovation Solution
A method involving the formation of a metallic material layer on the entire surface of the second electrode, followed by selective removal using energy rays, creating a resonance structure between reflective surfaces on the first and second substrates to accurately position auxiliary wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the film thickness of the transparent electrode is increased to lower sheet resistance, then electrical conductivity is improved, but light transmittance is reduced
Solution Approach 1:
The patent employs a composite structure consisting of a transparent electrode layer and a reflective electrode layer. The transparent electrode (e.g., ITO or IZO) provides both light transmittance and electrical conductivity, while the reflective electrode (e.g., aluminum) provides additional electrical conductivity and reflects light back through the transparent electrode, effectively lowering sheet resistance without compromising transmittance.
2Reliability
If auxiliary wiring is provided on the opposed substrate to lower sheet resistance, then electrical conductivity is improved, but manufacturing accuracy becomes difficult due to insulating layer formation challenges
Solution Approach 1:
Instead of providing auxiliary wiring on the opposed substrate (one-dimensional approach), the patent extends the transparent electrode and reflective electrode layers into the third dimension by forming them to overlap with the pixel region from the opposite side. This dimensional change eliminates the need for separate auxiliary wiring while achieving the same electrical conductivity improvement.
3Ease of manufacture
If mask vapor deposition is used to selectively coat light emitting units, then color display is achieved, but positioning accuracy requirements make it difficult for microdisplay applications
Solution Approach 1:
The patent extracts the color selection function from the deposition process itself and relocates it to the optical path. By depositing white light-emitting materials across the entire pixel region and then using color filters in the optical path, the complex mask positioning requirements are eliminated while maintaining selective color display capability.
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 method allows for the precise formation of auxiliary wiring on transparent electrodes, reducing sheet resistance and improving image quality by selectively removing the metallic material layer using energy absorption, thereby enhancing the manufacturing process for microdisplay devices.
Implementation Method 1
selectively removing the metallic material layer by energy absorbed by a part corresponding to the pixel
Implementation Method 2
a part corresponding to the pixel is configured to form a resonance structure for absorbing energy rays between a reflective surface on a side of the first substrate and a reflective surface on the second electrode
Data Source
AI summary
A method of manufacturing a display device including first electrodes provided for respective pixels, an insulating layer having openings respectively opposed to the first electrodes, an organic layer including a light emitting layer common to all the pixels, and a second electrode formed over an entire surface of the organic layer laminated on a first substrate, includes a step of forming an auxiliary wiring made of a metallic material layer by irradiating the metallic material layer with energy rays from a side of the metallic material layer and selectively removing the metallic material layer by energy absorbed by a part corresponding to the pixel after the metallic material layer has been formed on an entire surface of the second electrode.