Inkjet Head Electrode Ring Width Adjustment for Droplet Uniformity
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Solution Overview
Problem
Inkjet heads with non-uniform discharge droplet volumes from nozzles result in concentration distribution issues in output images, leading to decreased image quality, and existing correction methods are complex and lack a technical concept for adjusting the inflection point of the piezoelectric element's displacement profile.
Innovation Solution
The solution involves adjusting the ring width of the upper electrode in the piezo actuator to change the inflection point of the displacement profile, using correction coefficients to offset the in-plane distribution of the piezoelectric film thickness, thereby making the discharge droplet volumes uniform across the inkjet head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the thickness of the piezoelectric body film is not uniform across the wafer, then manufacturing is simplified, but the discharge droplet volumes from nozzles become non-uniform causing concentration distribution issues
Solution Approach 1:
The patent applies local quality by making the ring width of the upper electrode different for different zones on the wafer. Specifically, the ring width is set to be smaller in the central region and larger in the peripheral regions. This local variation in electrode geometry compensates for the non-uniform piezoelectric film thickness, ensuring uniform discharge droplet volumes across all nozzles despite the thickness variations.
2Manufacturing precision
If individual electrode widths are adjusted to correct piezoelectric film thickness variations, then discharge droplet volume uniformity is improved, but the correction process becomes complex
Solution Approach 1:
The patent changes the geometric parameter of the upper electrode (ring width) to correct the discharge uniformity issue. By systematically varying the ring width parameter across different wafer zones, the patent achieves compensation for piezoelectric film thickness variations without requiring complex multi-step correction procedures. This parameter-based approach simplifies the manufacturing process while maintaining high precision.
3Manufacturing precision
If the ring width of the upper electrode is adjusted to change the inflection point of the displacement profile, then discharge droplet volume uniformity is improved, but the electrode design becomes more complex
Solution Approach 1:
The patent introduces asymmetry in the upper electrode design by using different ring widths for different zones. The ring-shaped electrode is not uniformly sized across the wafer but is deliberately made asymmetric with smaller rings in the center and larger rings at the periphery. This asymmetric design allows precise control of the displacement profile inflection point to achieve uniform discharge.
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 effectively corrects the in-plane distribution of discharge droplet volumes, achieving high uniformity and improving image quality by ensuring consistent ink discharge from multiple nozzles.
Implementation Method 1
an actuator type inkjet head where a piezo actuator that transforms when voltage is applied
Data Source
Figure 1
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Figure 3A~3B
AI summary
A piezoelectric device and method of manufacturing the same and an inkjet head are described. In one embodiment, the inkjet print head comprises a plurality of jets, wherein each of the plurality of jets comprises a nozzle, a pressure chamber connected with the nozzle, a piezoelectric body coupled to the pressure chamber, and an electrode coupled to the piezoelectric body to cause displacement of the piezoelectric body to apply pressure to the pressure chamber in response to a voltage applied to the electrode; and wherein electrodes of two or more of the plurality of jets have different sizes to cause their associated piezoelectric bodies to have a uniform displacement amount when the voltage is applied to the electrodes.