Micromachined Fluid Ejector Array for Uniform Droplet Ejection
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Solution Overview
Problem
Conventional fluid ejectors, such as those used in printing and biochemistry, face challenges with large dead volumes, inefficient fluid distribution, and the inability to uniformly eject pico-liter quantities without satellite drops, making them unsuitable for precise biochemical applications.
Innovation Solution
A micromachined fluid ejector array utilizing a concentric array of piezoelectrically actuated flextensional transducers with a scalable array of orifices, where neighboring or all transducers can be actuated to eject fluid droplets in phase, reducing dead volume and enabling precise control over fluid ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large interconnected reservoir is used to store fluid, then the reservoir can be fully filled for ejection, but this results in large dead volume and waste of fluid
Solution Approach 1:
The patent divides the fluid storage system into multiple small, independent reservoirs instead of one large reservoir. Each reservoir is associated with specific nozzles and can be independently filled and emptied. This segmentation eliminates dead volume in unused portions while maintaining sufficient fluid capacity for complete ejection from each reservoir.
2Ease of operation
If long narrow passages are used to transmit ink to nozzles, then selective ejection can be achieved, but the passages increase device complexity and reduce ejection uniformity
Solution Approach 1:
The patent transitions from using long narrow passages (one-dimensional routing) to a planar membrane structure with integrated piezoelectric elements (two-dimensional arrangement). The membrane segments with piezoelectric elements are positioned directly adjacent to nozzle apertures, eliminating the need for complex passage routing while maintaining selective ejection capability through localized actuation.
3Ease of operation
If heaters are located at each nozzle to reduce ink viscosity, then selective ejection is improved, but the device complexity and energy consumption increase
Solution Approach 1:
The patent replaces the thermal field approach (heaters) with a mechanical field approach (piezoelectric transducers). The piezoelectric elements directly mechanically actuate the membrane segments to eject droplets, eliminating the need for thermal viscosity reduction and associated heater structures at each nozzle.
4Ease of operation
If piezoelectric elements are located on the membrane near nozzles, then selective membrane flexing is achieved, but the structure requires additional stiffening ribs that increase complexity
Solution Approach 1:
The patent merges the piezoelectric actuation function and the structural support function into a unified design. The piezoelectric elements are integrated directly into the membrane segments, and the membrane material itself provides the necessary structural support, eliminating the need for separate stiffening ribs and reducing overall structural complexity.
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 allows for reliable, low-waste, and uniform ejection of fluid droplets at high frequencies and resolutions, suitable for applications in biomedicine and precision manufacturing, such as organic light emitting devices and semiconductor manufacturing.
Implementation Method 1
A micromachined fluid ejector array utilizing a concentric array of piezoelectrically actuated flextensional transducers
Implementation Method 2
The fluid in the ejectors is bulk actuated to set up pressure waves in the fluid which cause fluid to form a meniscus at each orifice
Implementation Method 3
a two-dimensional array of elastic membranes having orifices closing the ends of cylindrical fluid reservoirs
Data Source
AI summary
This invention relates to a micromachined fluid ejector array having a fluid reservoir bounded at one side by an elastic membrane having scalable arrays of orifices arranged between concentric piezoelectric transducers, and at another side by a top cover supported by surrounding walls. By actuating neighboring concentric piezoelectric transducers, the scalable array of orifices arranged between the actuated neighboring concentric piezoelectric transducers deflect to eject fluid droplets. Also disclosed is a micromachined fluid ejector array having a fluid reservoir bounded at one side by an elastic membrane having scalable arrays of orifices arranged between concentric piezoelectric transducers, and at another side by a top cover supported by surrounding walls. A piezoelectric layer is bonded on top of the top cover. By actuating the piezoelectric layer bonded on top of the top cover, the scalable arrays of orifices arranged between the neighboring concentric piezoelectric transducers deflect in phase to eject fluid droplets.