Liquid Discharge Device Wiring Layout for Inductance Reduction
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Solution Overview
Problem
Existing liquid discharge devices face challenges in reducing the size and increasing the ink discharge rate due to increased peak current and overshoot voltage caused by higher ink discharge rates, as the number of wirings needed to manage the drive signal increases, leading to inefficiencies in existing solutions like JP-A-2019-005961.
Innovation Solution
A liquid discharge device with a wiring member that includes separate wiring patterns for drive signals, a reference voltage signal, and optimized surface arrangements to minimize inductance and current density, allowing for efficient ink discharge while maintaining a compact design, by providing the wiring patterns on different surfaces of a flexible substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of drive waveforms per unit time is increased to increase ink discharge rate, then the ink discharge rate is improved, but the peak current increases and overshoot voltage is superimposed due to mutual induction
Solution Approach 1:
The patent moves the reference voltage signal wiring from the same plane as drive signals to a different plane (second surface) of the flexible substrate, creating spatial separation in three-dimensional space. This dimensional change reduces mutual induction between drive signal wirings and reference voltage wiring, allowing higher ink discharge rates without excessive peak current and overshoot voltage.
Solution Approach 2:
The patent segments the wiring arrangement by separating drive signal wirings and reference voltage wiring onto different surfaces of the flexible substrate. This segmentation reduces the coupling between drive signals and reference voltage, minimizing mutual induction effects even when the number of drive waveforms per unit time is increased.
2Reliability
If the number of wirings is increased to manage the drive signal, then the waveform accuracy is improved, but the device size increases and it becomes difficult to reduce the size
Solution Approach 1:
The patent utilizes the third dimension by placing wirings on both surfaces of the flexible substrate. This allows drive signal wirings and reference voltage wiring to coexist without excessive interference, maintaining waveform accuracy while keeping the wiring layout compact and minimizing device size.
Solution Approach 2:
The flexible substrate serves multiple functions: it provides mechanical support, routes drive signals, and carries reference voltage wiring. By making the substrate itself multi-functional, the patent reduces the need for additional separate components, thereby maintaining waveform accuracy without increasing device size.
3Reliability
If the wiring is arranged to reduce mutual induction, then the overshoot voltage is reduced, but the device complexity increases
Solution Approach 1:
The patent reduces overshoot voltage by placing reference voltage wiring on a different surface from drive signal wirings. This spatial separation naturally reduces mutual induction without requiring complex shielding or routing patterns, thereby controlling overshoot voltage while maintaining relatively simple wiring arrangement.
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 reduces the size of the liquid discharge device and improves ink discharge accuracy by optimizing the wiring configuration, minimizing the inductance component and maintaining waveform accuracy even when the device is curved or deformed.
Implementation Method 1
a device using a piezoelectric element such as a piezo element is known. In such a liquid discharge device, a drive signal is supplied to the piezoelectric element to drive the piezoelectric element and discharge an amount of liquid corresponding to the drive of the piezoelectric element.
Implementation Method 2
the coupling member includes a first wiring that propagates the first drive signal, a second wiring that propagates the second drive signal, a third wiring that propagates a reference voltage signal serving as a reference potential for driving the drive element
Data Source
AI summary
A liquid discharge device including a discharge head, a head drive circuit that outputs a first drive signal, and a second drive signal, and a coupling member includes a first wiring that propagates the first drive signal, a second wiring that propagates the second drive signal, a third wiring that propagates a reference voltage signal, and a base material provided with the first wiring, the second wiring, and the third wiring, in which the first wiring and the second wiring are provided on a first surface of the base material, the third wiring is provided on a second surface different from the first surface of the base material, and at least one of the first wiring and the second wiring is located so as to overlap with at least a part of the third wiring in a first direction along a direction from the first surface to the second surface.