Centrally Positioned Inlets and Outlets for Fluid Ejection Uniformity
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Solution Overview
Problem
Fluid ejection devices face challenges in achieving uniform droplet size and directionality, leading to inconsistent deposition on a medium, particularly due to limitations in nozzle design and fluid path configurations.
Innovation Solution
The design incorporates a substrate with multiple nozzle regions separated by a gap region, featuring inlets and outlets positioned near the middle, which are fluidically connected to form microfabricated fluid flow paths, allowing for individually controllable MEMS fluid ejectors and reducing pressure drops and interference between nozzles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If nozzles are arranged in a single continuous region, then device complexity is reduced, but droplet uniformity and directionality deteriorate due to pressure drops and fluid interference between nozzles
Solution Approach 1:
The nozzle array is divided into multiple separated regions with gaps between them. This segmentation prevents fluid interference between adjacent nozzle groups and minimizes pressure drops by creating distinct fluid flow zones. Each region can be independently optimized for uniform droplet ejection while the gaps eliminate cross-interference between regions.
2Manufacturing precision
If inlets and outlets are positioned at the edges of the substrate, then ease of connection is improved, but fluid travel distance increases causing greater pressure drops and reduced ejection uniformity
Solution Approach 1:
The inlet and outlet positions are moved from traditional edge locations to the central region of the substrate, utilizing the central dimension more effectively. This repositioning creates shorter fluid travel paths to all nozzle regions while the alternating inlet-outlet pattern along the perimeter provides multiple connection points, balancing both uniformity and connection ease.
3Area of stationary object
If nozzle regions are placed close together, then substrate area utilization is improved, but fluid interference between regions increases causing pressure fluctuations and droplet inconsistency
Solution Approach 1:
Different regions of the substrate are assigned different functions: nozzle regions are densely packed for area utilization, while gap regions are specifically designed as fluid isolation zones. The alternating inlet-outlet configuration creates localized pressure zones that prevent fluid interference between adjacent nozzle regions, allowing dense packing without sacrificing droplet consistency.
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 configuration enhances the uniformity and reliability of fluid droplet ejection by minimizing pressure drops and fluid travel distances, improving the surface area for electrical connections and bonding, and reducing the risk of leaks and electrical shorts.
Implementation Method 1
The transducer can be actuated by a voltage applied by a trace that electrically connects the transducer to a voltage source, such as an application-specific integrated circuit (ASIC)
Data Source
AI summary
An apparatus for ejecting droplets of a fluid includes a substrate, a first plurality of nozzles formed in a first region of a nozzle face of the substrate, and a second plurality of nozzles formed in a second region of the nozzle face. The second region is separated from the first region. An inlet and an outlet are both formed in an upper face of the substrate opposite a third region of the nozzle face, the third region being located between the first region and the second region, and a plurality of fluid paths formed in the substrate and fluidically connecting the first plurality of nozzles and the second plurality of nozzles with the inlet and outlet.