Liquid Discharge Head Wiring Substrate Electrode Arrangement
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Solution Overview
Problem
In liquid discharge apparatuses, such as ink jet printers, variations in wiring length for drive signal propagation can lead to reduced inspection accuracy due to the configuration of bump electrodes connecting the drive IC, actuator substrate, and interposer substrate.
Innovation Solution
A liquid discharge head with a wiring substrate that includes specific electrode arrangements to minimize variations in wiring length, where the second electrode is positioned between the first and third electrodes along a longer side, and the third and fourth electrodes are positioned between the second electrode and the drive IC, allowing for improved signal propagation and inspection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If bump electrodes are used to electrically connect the drive IC, actuator substrate, and interposer substrate, then the liquid discharge head can be miniaturized, but variations in wiring length for drive signal propagation occur, reducing inspection accuracy
Solution Approach 1:
The patent segments the electrode connections into multiple paths (first signal path through first and second electrodes, second signal path through third and fourth electrodes) to provide alternative routing options. This segmentation allows optimization of signal propagation paths while maintaining compact head size, thereby reducing wiring length variations and improving inspection accuracy.
Solution Approach 2:
The patent utilizes the planar dimension of the wiring substrate by arranging electrodes in specific two-dimensional patterns (first electrode, second electrode, third electrode, and fourth electrode positioned at different locations). This dimensional arrangement optimizes signal paths without increasing the overall head volume, resolving the contradiction between miniaturization and inspection accuracy.
2Ease of operation
If multiple inspection terminals are provided at the end portion of the nozzle line, then drive signal inspection can be performed, but variations in wiring length occur, lowering inspection accuracy
Solution Approach 1:
The patent applies local quality by providing multiple inspection terminals (first inspection terminal and second inspection terminal) at different locations on the wiring substrate. Each terminal is strategically positioned to minimize wiring length variations for specific signal paths, allowing drive signal inspection to be performed with improved accuracy at each local inspection point.
Solution Approach 2:
The patent introduces intermediate electrodes (second electrode and fourth electrode) that serve as mediators between the drive IC and inspection terminals. These intermediary electrodes optimize the signal propagation path by reducing wiring length variations, thereby improving the accuracy of drive signal inspection while maintaining ease of operation.
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 reduces variations in wiring resistance and signal waveform, enhancing the inspection accuracy of drive signals in liquid discharge apparatuses by optimizing the electrode positioning on the wiring substrate.
Implementation Method 1
a drive element such as a piezoelectric element provided in a liquid discharge head
Data Source
AI summary
There is provided a liquid discharge head including a drive IC that outputs the first signal and the second signal, and a wiring substrate having a first side and a second side longer than the first side, electrically connected to the drive IC, and propagating the first signal and the second signal, in which the wiring substrate includes a first electrode to which the first signal is input, a second electrode to which the second signal is input, a third electrode electrically connected to the first electrode, and a fourth electrode electrically connected to the second electrode, and in a direction along the second side, the second electrode is positioned between the first electrode and the third electrode, and the third electrode is positioned between the second electrode and the fourth electrode.