Maskless Photosensitive OLED Pixel Definition for High Density
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Solution Overview
Problem
Current OLED manufacturing techniques limit pixel density due to the constraint of mask sizes, making it difficult to achieve higher than 800 ppi pixel definition.
Innovation Solution
The method involves forming light emitting units using a photosensitive material directly on a substrate without a mask, employing photolithography for pixel definition, and layering techniques such as carrier transportation and injection layers to achieve high pixel density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mask is used to coat light emitting material on a substrate, then the pixel definition is realized, but the critical dimension on the mask cannot be smaller than 100 microns, limiting pixel density to below 800 ppi
Solution Approach 1:
The patent removes the mask component from the manufacturing process entirely. Instead of using a physical mask to define pixels, the invention uses a photosensitive layer that is directly patterned on the substrate through photolithography. This extraction of the mask enables critical dimensions to be reduced below 100 microns, achieving pixel densities exceeding 800 ppi while maintaining precise pixel definition.
2Adaptability or versatility
If the critical dimension on the mask is reduced to increase pixel density, then higher pixel density can be achieved, but the mask manufacturing and alignment complexity increases significantly
Solution Approach 1:
The patent replaces the mechanical mask system with a photolithographic patterning system. Instead of physically reducing mask dimensions and dealing with mask alignment, the invention uses light-based photolithography to directly pattern the photosensitive layer on the substrate. This substitution eliminates mask manufacturing and alignment complexity while enabling high pixel density through precise optical patterning.
3Adaptability or versatility
If photolithography is used to define pixels without a mask, then pixel density exceeding 800 ppi can be achieved, but additional layers (photosensitive layer, buffer layer) must be formed and processed
Solution Approach 1:
The patent applies preliminary action by forming the photosensitive layer and buffer layer structures before depositing the light emitting material. The photosensitive layer is patterned first to define the pixel regions, then the buffer layer is formed to provide a foundation for subsequent light emitting material deposition. This preliminary structuring enables high pixel density while organizing the additional layers in a systematic sequence that facilitates subsequent manufacturing steps.
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 OLEDs with pixel densities exceeding 1200 ppi by allowing precise control over light emitting unit size and spacing, enhancing display resolution.
Implementation Method 1
The pixel definition is realized by a photolithography process
Data Source
AI summary
A method of manufacturing a light emitting device includes providing a substrate, forming a plurality of photosensitive bumps over the substrate, forming a photosensitive layer over the plurality of photosensitive bumps, forming a buffer layer between the photosensitive layer and the plurality of photosensitive bumps, patterning the photosensitive layer to form a recess through the photosensitive layer to expose a surface, disposing an organic emissive layer on the surface, forming a metal containing layer over the organic emissive layer, and removing the patterned photosensitive layer.