Evaporation Mask Curved Holes Co-Doping OLED
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Solution Overview
Problem
Existing evaporation masks with straight holes hinder the reliable co-doping of materials in OLED display panel manufacturing, leading to layering issues and degraded device performance due to the inability to achieve close proximity of evaporation sources and inadequate aperture sizes.
Innovation Solution
An evaporation mask with non-straight through-holes, featuring varying through-hole angles and apertures that allow for flexible nozzle orientation, enabling co-doping of different materials by adjusting evaporation angles to ensure precise deposition on a to-be-evaporated substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If straight through-holes are used in the evaporation mask, then the mask structure is simple and easy to manufacture, but the evaporation sources cannot be positioned closely enough leading to layering issues and poor co-doping reliability
Solution Approach 1:
The patent applies curvature by transforming the straight through-holes into arc-shaped through-holes. The arc-shaped holes enable the evaporation mask to be positioned at an angled relationship with the substrate, allowing evaporation sources to be placed closer together while preventing material layering. The curved geometry provides optimized material deposition paths that straight holes cannot achieve.
Solution Approach 2:
The patent introduces angular positioning as an additional dimension of control. By positioning the evaporation mask at a specific angle relative to the substrate and utilizing arc-shaped holes, the system achieves precise material deposition control in multiple spatial dimensions, enabling close proximity of evaporation sources without compromising deposition accuracy.
2Reliability
If the aperture of evaporation through-holes is increased to allow closer evaporation sources, then co-doping becomes possible, but the aperture size becomes insufficient for high pixel density requirements
Solution Approach 1:
The arc-shaped through-holes with optimized radius enable precise control of material deposition patterns. The curved geometry, combined with angled mask positioning, allows the aperture to be sized appropriately for high pixel density while still enabling evaporation sources to be positioned close enough for effective co-doping.
Solution Approach 2:
The patent optimizes specific parameters including the arc radius (5-20 μm), mask positioning angle (30-60 degrees), and aperture dimensions to simultaneously achieve close evaporation source positioning and high pixel density precision. These parameter adjustments enable both co-doping capability and manufacturing precision.
3Reliability
If evaporation sources are positioned closely for co-doping, then material co-doping is achieved, but the fixed straight hole geometry prevents flexible nozzle orientation
Solution Approach 1:
The arc-shaped through-holes provide geometric flexibility that enables evaporation nozzles to be oriented at various angles while maintaining precise material deposition. The curved hole geometry accommodates different nozzle orientations better than straight holes, enhancing adaptability for co-doping operations.
Solution Approach 2:
By introducing angular positioning of the mask relative to the substrate as an additional degree of freedom, the system achieves flexible nozzle orientation capability. The combination of arc-shaped holes and angled positioning allows evaporation sources to approach from different directions while maintaining precise deposition control.
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 solution enables reliable co-doping of materials, preventing layering and ensuring high device performance by allowing for precise material deposition across sub-pixel regions, even at high pixel densities.
Implementation Method 1
an evaporation source is disposed on one side of the evaporation mask distal to the to-be-evaporated substrate... the evaporation source is configured to evaporate a material onto a sub-pixel region of the to-be-evaporated substrate through the evaporation through-hole
Data Source
AI summary
Provided is an evaporation mask, including a mask plate and a plurality of evaporation through-holes. The evaporation through-holes penetrate through the mask plate and corresponds to the sub-pixel regions one by one such that a plurality of sub-pixels of different colors are formed in the plurality of sub-pixel regions; and wherein for each of the evaporation through-holes, an aperture of an opening of the evaporation through-hole on a side proximal to the to-be-evaporated substrate is less than an aperture of an opening of the evaporation through-hole on a side distal to the to-be-evaporated substrate, the opening of the evaporation through-hole on the side distal to the to-be-evaporated substrate extends to at least one adjacent sub-pixel region, and a color of a sub-pixel evaporated in a sub-pixel region corresponding to the evaporation through-hole is different from a color of a sub-pixel evaporated in the at least one adjacent sub-pixel region.