OVJP Flow Tube Aperture Array for Lag Time Reduction

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Solution Overview

Problem

Current organic vapor jet printing (OVJP) systems experience high lag times and inefficiencies due to suboptimal conductance paths and nozzle sizes, leading to prolonged stabilization times and transients in organic material deposition, particularly in high-resolution applications.

Innovation Solution

A high-throughput OVJP system with a flow tube and multiple apertures, where a bypass valve controls the flow path conductance, allowing for a significant conductance ratio between the bypass and deposition paths, enabling rapid switching and minimizing transients, with apertures and nozzles optimized for high conductance and reduced lag times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a small nozzle or aperture is used for high-resolution deposition, then manufacturing precision is improved, but device productivity deteriorates due to low conductance and long lag times

Engineering Contradiction:
Improvedeposition resolutionVSAvoiddeposition rate
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The system divides the flow path into multiple parallel apertures instead of using a single small nozzle. This segmentation allows each aperture to maintain small dimensions for high resolution while the collective array provides sufficient total conductance for high productivity, resolving the contradiction between precision and rate.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-point deposition (0D/1D) to a multi-point array deposition (2D/3D). By arranging multiple apertures in a spatial array, the system achieves high resolution at each point while the overall system conductance is multiplied, simultaneously improving precision and productivity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If a long flow path is used for precise material transport, then manufacturing precision is improved, but device complexity increases and lag time increases

Engineering Contradiction:
Improvematerial placement accuracyVSAvoidflow path configuration
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates unnecessary intermediate flow path elements between the source and substrate. By using a direct, short flow path with multiple apertures close to the substrate, the system achieves precise material placement without the complexity and lag time associated with long, convoluted flow paths.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system pre-positions multiple apertures in optimal locations on the flow tube, allowing direct deposition onto the substrate without requiring complex in-transit material manipulation. This preliminary arrangement of deposition points simplifies the flow path and reduces lag time while maintaining precision.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If a bypass valve with high conductance ratio is used for rapid switching, then device productivity is improved, but device complexity increases

Engineering Contradiction:
Improveswitching speedVSAvoidvalve control system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention changes the conductance parameter of the bypass valve to be at least 100 times greater than the aperture conductance. This extreme parameter difference creates a natural, rapid switching mechanism where the valve either fully bypasses flow or fully directs it through apertures, achieving high productivity with simple on/off control rather than complex modulation.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If multiple apertures are used instead of a single nozzle, then device productivity is improved, but manufacturing precision may deteriorate due to pattern alignment difficulties

Engineering Contradiction:
Improvedeposition throughputVSAvoidpattern alignment
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention merges multiple aperture functions into a single integrated array structure on the flow tube. This unified structure ensures precise relative positioning of all apertures, maintaining pattern alignment precision while achieving high throughput through parallel deposition at multiple locations simultaneously.

Inventive Principle:
Principle #5Merging (Combining)

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 system achieves significantly reduced lag times, often less than 1 minute, and increased deposition efficiency by ensuring that organic molecules follow high-conductance paths during charging and low-conductance paths during deposition, stabilizing the deposition rate quickly and maintaining constant output.

Implementation Method 1

a source of organic molecules in fluid communication with the enclosure, a source of carrier gas in fluid communication with the source of organic molecules

Methodology Applied
Scientific EffectVapor flow: Advection

Implementation Method 2

Methods and systems are provided for the deposition of organic materials

Methodology Applied
Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentEP2475800B1Method and system for deposition of patterned organic thin films
Publication Date: 2020.04.22 UNIVERSAL DISPLAY CORP
  • EP2475800B1 patent drawingFigure 1
  • EP2475800B1 patent drawingFigure 2~3
  • EP2475800B1 patent drawingFigure 4A~4B

AI summary

High-throughput OVJP systems and methods are provided that may use multiple flow paths having different conductances to enable deposition with relatively short lag times. A high-throughput OVJP system may include a flow tube having a cross-sectional area much larger than the diameter of one or more apertures through which source material may be expelled during deposition. Use of such a configuration may allow for deposition with reduced lag times.