Liquid Supply Substrate With Intermediate Layer For Thermal Management
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Solution Overview
Problem
In liquid ejecting heads, the heat generated by electrothermal conversion elements is transferred to the ink through the silicon substrate, leading to increased ink temperature and reduced heat dissipation efficiency, resulting in unstable ejection.
Innovation Solution
A liquid supply substrate with a three-layered structure comprising a first silicon substrate, a second silicon substrate, and an intermediate layer with regions of varying thermal conductivity, where the intermediate layer includes a silicon oxide film and a hollow region, reducing heat transfer to the substrate and improving heat dissipation efficiency by directing thermal energy mainly to the liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat is transferred from the electrothermal conversion element to the substrate, then the substrate temperature increases, but the ink temperature also increases leading to reduced heat dissipation efficiency
Solution Approach 1:
The intermediate layer is designed with spatially varying thermal conductivity: it has high thermal conductivity in the first region (away from the electrothermal conversion element) to conduct heat away from the substrate, and low thermal conductivity in the second region (under the electrothermal conversion element) to prevent heat transfer to the ink. This local differentiation of thermal properties resolves the contradiction by allowing heat management in different locations to serve different purposes.
Solution Approach 2:
The intermediate layer acts as a thermal mediator between the electrothermal conversion element and the substrate. By controlling the thermal conductivity distribution within this intermediate layer, it selectively transmits or blocks heat flow in different regions, thereby mediating the thermal interaction to achieve both substrate cooling and ink temperature stabilization.
2Temperature
If the ink temperature is increased by heat transfer from the substrate, then the substrate can be cooled, but the heat dissipation efficiency of the electrothermal conversion element is reduced
Solution Approach 1:
The intermediate layer implements local quality control by having different thermal conductivity values in different regions. The first region allows heat to be conducted away from the substrate to prevent overheating, while the second region blocks heat transfer to the ink, ensuring that ink temperature remains stable and heat dissipation efficiency is maintained.
Solution Approach 2:
The intermediate layer serves as a thermal mediator that selectively controls heat flow paths. It mediates between the electrothermal conversion element and the surrounding structures, allowing heat to be directed toward the substrate in the first region while blocking heat transfer to the ink in the second region, thus preserving heat dissipation efficiency.
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 minimizes the increase in substrate temperature and enhances the heat dissipation efficiency of electrothermal conversion elements during ejection, stabilizing the ejection process.
Implementation Method 1
an intermediate layer disposed between the first substrate and the second substrate, the intermediate layer including a first region and a second region having lower thermal conductivity than the first region
Data Source
AI summary
A first substrate including a plurality of supply ports through which a liquid is supplied to a position of an electrothermal conversion element and a second substrate including a common liquid supply chamber from which the liquid is supplied to the plurality of supply ports are coupled together with an intermediate layer therebetween. The intermediate layer includes a first region and a second region having lower thermal conductivity than the first region.