Electrowetting Liquid Transport Apparatus for Compact Inkjet Heads
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Solution Overview
Problem
Conventional ink-jet recording heads face limitations in reducing size due to complex nozzle arrangements and ink ejection mechanisms, which hinder high-density nozzle placement and efficient ink discharge.
Innovation Solution
A liquid transport apparatus utilizing electrowetting phenomenon with a substrate having insulating surfaces, conductive liquid transport channels, electrodes, and insulating layers that change wetting angles in response to electrical potential differences, allowing for controlled ink discharge without the need for complex nozzle structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional ink-jet recording head structures are used with complex nozzle arrangements and ink ejection mechanisms, then ink discharge function is achieved, but device size cannot be reduced and high-density nozzle arrangement is hindered
Solution Approach 1:
The patent replaces the conventional mechanical ink ejection mechanism (nozzles, actuators, complex flow passages) with an electrowetting-based system. The electrowetting phenomenon uses electrical fields to change the wetting properties of surfaces, enabling ink ejection through controlled changes in surface energy rather than mechanical force. This substitution dramatically simplifies the device structure while enabling compact, high-density nozzle arrangements.
Solution Approach 2:
The invention utilizes changes in electrical potential as a control parameter to modulate the wetting angle of the insulating layer surface. By applying different voltages to the electrodes, the surface energy of the insulating layer is dynamically adjusted, controlling ink flow and ejection. This parameter-based control eliminates the need for complex mechanical actuators and enables precise, compact ink discharge mechanisms.
2Device complexity
If electrowetting phenomenon is used with insulating layers and electrodes, then device structure is simplified and size is reduced, but control of ink flow and discharge requires precise electrical potential management
Solution Approach 1:
The electrowetting system is inherently self-regulating through the physics of surface tension and wetting angles. The insulating layer automatically responds to applied voltages by adjusting its surface properties, eliminating the need for complex feedback control systems. The system self-adjusts ink flow based on the electrical potential applied, reducing the difficulty of precise control while maintaining simplicity.
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
Enables efficient and stable ink transport with simplified manufacturing, reduced costs, and improved integration density by leveraging electrowetting to manage ink flow and discharge effectively.
Implementation Method 1
a first insulating layer which is disposed so as to cover the electrodes on the insulating surface of the substrate and in which a wetting angle with respect to the conductive liquid changes according to an electrical potential difference between the conductive liquid and the electrodes
Data Source
AI summary
A liquid transport apparatus includes liquid transport channels disposed on an insulating surface of a substrate, individual electrodes disposed in regions corresponding to respective ones of the liquid transport channels, and wiring portions extending along the insulating surface of the substrate. The apparatus further includes a first insulating layer disposed so as to cover the electrodes and in which the wetting angle with respect to a conductive liquid changes according to an electrical potential difference between the conductive liquid and the electrodes, a second insulating layer which is disposed so as to cover the wiring portions disposed in contact with the first insulating layer, and a potential applying unit which applies an electric potential to the electrodes.