Liquid Ejection Head Heat Dissipation via Segmented Thermal Bridge
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Solution Overview
Problem
Existing liquid ejection heads face challenges in efficiently dissipating heat generated by energy generation elements, leading to localized heating on the substrate, which restricts the arrangement of drive circuits and transistors, hindering the downsizing of the device.
Innovation Solution
Incorporating a heat transmitting member that connects a high thermal conductivity heat transmitting layer to the substrate, but excluding the area directly below the energy generation element, allowing for dispersed heat dissipation and creating space for drive circuits and transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat is conducted intensively to an area near the energy generation element on the substrate, then heat dissipation efficiency is improved, but the area for arranging drive circuits and transistors is reduced
Solution Approach 1:
The heat transmitting member is divided into multiple independent heat transmitting portions that are distributed across the substrate surface. Each portion independently conducts heat from the energy generation element to different areas of the substrate, segmenting the heat dissipation function to avoid concentration in a single area.
Solution Approach 2:
The heat transmission is extended from a single-point or single-area contact to multiple distributed contact areas across the substrate surface. By spreading the heat transmitting portions in the planar dimension, the patent transforms the heat dissipation from a localized vertical conduction to a distributed three-dimensional heat distribution network.
2Loss of energy
If heat transmitting member is positioned directly below the energy generation element, then heat conduction efficiency is improved, but device downsizing is hindered due to space requirements for drive circuits
Solution Approach 1:
The heat transmitting member is segmented into multiple heat transmitting portions that can be distributed across available substrate areas. This segmentation allows the drive circuits and transistors to be arranged in the area directly below the energy generation element while maintaining effective heat conduction through the distributed portions.
Solution Approach 2:
The substrate serves multiple functions: it acts as both the structural support and the heat dissipation medium through the distributed heat transmitting portions. The substrate's large surface area is utilized for both circuit arrangement and heat conduction, eliminating the need for separate heat sink structures.
3Power
If heat is stored in the energy generation element, then liquid ejection performance is improved, but bubble generation due to excessive heat storage occurs
Solution Approach 1:
The distributed heat transmitting portions continuously conduct heat from the energy generation element to the substrate during operation. This continuous heat removal prevents heat accumulation that would lead to excessive temperature rise and bubble generation, while maintaining the temperature conditions necessary for liquid ejection.
Solution Approach 2:
The heat transmitting portions act as intermediaries between the energy generation element and the substrate. They efficiently transfer heat from the energy generation element to the substrate's heat dissipation areas, serving as a thermal bridge that prevents both heat storage (which would improve ejection) and excessive heat accumulation (which would cause bubbles).
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 effectively suppresses intense heat conduction to the substrate, enabling the arrangement of drive circuits and transistors, thus allowing for the downsizing of the liquid ejection head while maintaining efficient liquid ejection performance.
Implementation Method 1
at least one heat transmitting layer which is composed of a material having a higher thermal conductivity than that of a material of the insulating layer and which is provided, in the insulating layer, between the energy generation element and the substrate
Implementation Method 2
a heat transmitting member which thermally connects the at least one heat transmitting layer and the substrate
Data Source
AI summary
A liquid ejection head having at least one energy generation element for generating heat to be used for ejecting a liquid includes an insulating layer which is provided in contact with a substrate and supports the energy generation element; at least one heat transmitting layer which is composed of a material having a higher thermal conductivity than that of a material of the insulating layer and which is provided, in the insulating layer, between the energy generation element and the substrate; and a heat transmitting member which thermally connects the at least one heat transmitting layer and the substrate, wherein the heat transmitting member is connected to an area, on the heat transmitting layer, excluding an area directly below the energy generation element in a position interposed between the energy generation element and the substrate.