Piezo Inkjet IC Layout for Stable Drive Signal Output

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Solution Overview

Problem

Existing liquid ejecting apparatuses with piezoelectric elements face malfunctions due to suboptimal circuit arrangements within the integrated circuit, leading to instability in the operation of the drive circuit, which is not adequately addressed in existing technologies.

Innovation Solution

The proposed solution involves a specific configuration of the integrated circuit within the liquid ejecting apparatus, including a drive circuit with a power supply voltage control circuit, a drive signal discharge circuit, and a modulation circuit, which optimizes the arrangement of components such as the discharge circuit, constant voltage output circuit, and modulation circuit to improve signal interference reduction and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If multiple circuits (discharge circuit, constant voltage output circuit, modulation circuit) are integrated into a single integrated circuit, then the device complexity is reduced and space is saved, but signal interference increases and operational stability deteriorates

Engineering Contradiction:
Improvecircuit arrangementVSAvoidoperational stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The integrated circuit is divided into distinct functional regions: a discharge circuit region, a constant voltage output circuit region, and a modulation circuit region. Each region is spatially separated to minimize signal interference while maintaining functional integration within the same integrated circuit package.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the integrated circuit are designed with locally optimized characteristics appropriate to their function. The discharge circuit region is positioned and configured to handle high-current discharge operations, while the modulation circuit region is optimized for precision signal processing, with each region having tailored electrical properties and shielding arrangements.

Inventive Principle:
Principle #3Local quality

2Area of stationary object

If the discharge circuit is positioned close to the modulation circuit, then the circuit area is reduced, but signal interference from the discharge circuit to the modulation circuit increases

Engineering Contradiction:
Improveintegrated circuit areaVSAvoidsignal interference
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

A shielding structure is introduced as an intermediary element between the discharge circuit and the modulation circuit. This shielding structure acts as a barrier that blocks electromagnetic interference from the discharge circuit while allowing the circuits to remain in close proximity for space efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of separating the discharge circuit and modulation circuit only in the planar direction, the solution utilizes the vertical dimension by positioning one circuit above or below the other with shielding structures in between, effectively using three-dimensional space to reduce interference while maintaining compact footprint.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If the constant voltage output circuit is optimally positioned to reduce interference, then signal quality improves, but the circuit layout complexity increases

Engineering Contradiction:
Improvesignal qualityVSAvoidcircuit layout
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The constant voltage output circuit is designed to serve multiple functions: it provides stable voltage reference for the modulation circuit, supplies power to other circuit blocks, and acts as a buffer between the discharge circuit and other sensitive circuits. This multi-functionality justifies its centrally positioned layout.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enhances the stability and accuracy of the drive signal output, reducing the likelihood of malfunctions and improving the ink ejection precision in the liquid ejecting apparatus.

Implementation Method 1

a piezoelectric element such as a piezo element are known. Such a piezoelectric element is provided corresponding to a plurality of nozzles for ejecting ink

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3842234B1Liquid ejecting apparatus, drive circuit, and integrated circuit
Publication Date: 2023.03.22 SEIKO EPSON CORP
  • EP3842234B1 patent drawingFigure 1
  • EP3842234B1 patent drawingFigure 2
  • EP3842234B1 patent drawingFigure 3

AI summary

A liquid ejecting apparatus includes a liquid ejecting head ejecting a liquid by supplying a drive signal to a drive element, and a drive circuit. The drive circuit includes an integrated circuit, an amplifier circuit that operates according to the amplification control signal to output an amplified modulation signal, and a demodulation circuit. The integrated circuit includes a modulation circuit that modulates the base drive signal to output a modulation signal, a switching circuit that outputs the amplification control signal according to the modulation signal, and a constant voltage output circuit that outputs a DC voltage signal based on the output of the modulation circuit. The constant voltage output circuit and the modulation circuit are electrically coupled to each other, and at least a part of the constant voltage output circuit is located between the modulation circuit and the switching circuit.