Fluidic Die Selector Placement for Parasitic Capacitance
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Solution Overview
Problem
Fluidic dies in systems like printers and additive manufacturing devices face issues such as clogging, particle contamination, and surface damage, leading to inaccurate actuator state determination due to varying parasitic capacitance along transmission paths, which can result in incorrect classification of fluid actuator states.
Innovation Solution
The fluidic die design includes selectors coupled in parallel to the measurement device, with each selector adjacent to the respective firing subassembly, ensuring uniform parasitic capacitance along the transmission paths, allowing for consistent and accurate actuator evaluation by maintaining equidistant and short paths between selectors and sensor plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If transmission paths between selectors and measurement device are made longer to accommodate device layout, then device complexity is reduced, but measurement precision deteriorates due to varying parasitic capacitance
Solution Approach 1:
The patent applies equipotentiality by configuring all selector-to-measurement-device transmission paths to have equal length and identical routing characteristics. This ensures that all paths have the same parasitic capacitance values, creating electrically equivalent conditions for signal transmission. By making the transmission paths equipotential in terms of electrical characteristics, the measurement device receives consistent signal quality regardless of which selector is active, thereby maintaining measurement precision while allowing flexible device layout.
2Ease of manufacture
If selectors are placed farther from sensor plates to simplify routing, then ease of manufacture improves, but measurement precision deteriorates due to increased parasitic capacitance
Solution Approach 1:
The patent applies parameter changes by optimizing the physical dimensions and electrical characteristics of the transmission paths. Specifically, it controls the length, width, and trace geometry of the conductive paths to maintain consistent parasitic capacitance values. By adjusting these physical parameters, the design achieves a balance where selectors can be positioned for manufacturing convenience while the transmission path characteristics are tuned to minimize and equalize parasitic effects, thereby preserving measurement precision.
3Area of stationary object
If transmission paths have unequal lengths to accommodate compact device layout, then device area is reduced, but measurement precision deteriorates due to parasitic capacitance variations
Solution Approach 1:
The patent applies local quality by making the transmission path characteristics dependent on their specific location and routing rather than using a uniform approach. Each transmission path is individually designed with specific trace geometry, length, and routing to compensate for its unique position in the device layout. This allows unequal physical path lengths to result in equal electrical characteristics, as each path's local properties are optimized to achieve the same parasitic capacitance values, thereby maintaining measurement precision in a compact device area.
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 design ensures accurate and repeatable actuator state determination, reducing errors caused by parasitic capacitance variations, thereby improving the reliability of actuator health assessments and subsequent calibration processes.
Implementation Method 1
varying parasitic capacitance along transmission paths
Data Source
AI summary
In one example in accordance with the present disclosure, a fluidic die is described. The fluidic die includes an array of firing subassemblies grouped into zones. Each firing subassembly includes 1) a firing chamber, 2) a fluid actuator, and 3) a sensor plate. The fluidic die also includes a measurement device per zone to measure a voltage indicative of an impedance within a selected firing chamber. The fluidic die includes a selector per firing subassembly to couple a selected sensor plate to the measurement device. A selector is adjacent a respective firing subassembly and a distance between the selector and the measurement device is different as compared to other selectors.