Inkjet Dispenser Third Harmonic Dwell Time Optimization
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Solution Overview
Problem
Current inkjet dispensers operating at the first harmonic dwell region produce irregular drop morphology and satellite droplets, making accurate targeting and quantitation challenging.
Innovation Solution
Operating the inkjet dispenser at a dwell time corresponding to the third harmonic by multiplying the first harmonic dwell time by a factor of three and fine-tuning to achieve consistent drop morphology and maximum drop mass, independent of driving amplitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the inkjet dispenser operates at the first harmonic dwell region, then the operation is simplified and commonly used, but the drop morphology becomes irregular with satellites and amorphous shapes
Solution Approach 1:
The patent changes the operating parameter from first harmonic dwell region to third harmonic dwell region. Specifically, it sets the dwell time to correspond to the third harmonic resonance frequency of the acoustic pressure waves in the inkjet channel, which transforms the pressure wave patterns and their constructive interference, resulting in consistent round drop morphology while maintaining operational feasibility
2Ease of manufacture
If the inkjet dispenser operates at the first harmonic dwell region, then the setup is straightforward, but quantitation by optical techniques becomes extremely challenging
Solution Approach 1:
The patent changes the operating parameter from first harmonic to third harmonic dwell region, which produces consistent round drop morphology. This morphological consistency directly improves optical quantitation accuracy because regular spherical shapes provide predictable light scattering and reflection patterns, making optical measurement and quantitation significantly more reliable while the setup remains straightforward
3Manufacturing precision
If the inkjet dispenser operates at higher dwell regions corresponding to third harmonic, then consistent round drop morphology is achieved, but the operation complexity increases
Solution Approach 1:
The patent utilizes periodic acoustic pressure waves at the third harmonic resonance frequency. By establishing a periodic driving waveform that matches the third harmonic resonance period of the inkjet channel, the system achieves constructive interference of pressure waves at regular intervals, producing consistent round drop morphology through periodic reinforcement of the ejection mechanism
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 results in consistent, round drop morphology with high drop mass, improving targeting accuracy and simplifying quantitation by optimizing drop ejection at higher harmonic resonance points.
Implementation Method 1
The piezoelectric element is dimensionally perturbed by increasing and/or decreasing driving amplitudes (electric voltages), which expand and contract its diameter. These expansions and contractions produce pressure waves within the glass tube
Implementation Method 2
By operating at or near the harmonic frequency or resonance frequency, the maximum coincidence may be achieved. In typical inkjet operation, this means operation at a dwell setting or time corresponding to the first harmonic of acoustic pressure wave reverberation inside of the inkjet channel or tube
Data Source
AI summary
A method for improving the morphology of drops ejected from inkjet dispensers results in a more accurate and repeatable process. The method involves shifting the dwell time from one corresponding to the first harmonic of the dispenser to a higher harmonic, for example, the third harmonic.