Thermal Head Bonding Protrusion for Heat Dissipation

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Solution Overview

Problem

Existing thermal heads for printing devices face challenges in efficiently dissipating heat and maintaining durability, particularly in the connection structure between electronic components and substrates.

Innovation Solution

The thermal head design incorporates a heat dissipation body, a head base with a substrate, heat generating parts, and a flexible printed circuit board (FPC) connected using an electrically conductive bonding material with a protruding portion, enhancing heat dissipation and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If solder is used to fix electronic components to substrate with fillet shape, then electrical connection is achieved, but heat dissipation efficiency is insufficient

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidconnection durability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent changes the shape parameter of the bonding material from conventional fillet shape to protruding shape that extends beyond the electronic component. This geometric parameter change increases the bonding surface area and improves heat dissipation efficiency while maintaining reliable electrical connection.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The bonding material is designed to protrude in the thickness direction from the substrate, adding vertical dimension to the bonding structure. This dimensional extension increases the contact area between bonding material and underfill material, enhancing both heat dissipation pathway and mechanical durability.

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

2Reliability

If conventional bonding material shape is used, then manufacturing is simple, but contact area with underfill material is insufficient leading to peeling or breakage

Engineering Contradiction:
Improveconnection durabilityVSAvoidbonding material structure complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The bonding material shape is modified to have a protruding portion that extends beyond the electronic component in the thickness direction. This parameter change increases the contact area with underfill material, preventing peeling and breakage, while still being manufacturable using existing processes.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If heat generating portions are arranged in main scanning direction, then printing function is achieved, but heat accumulation occurs reducing printing quality

Engineering Contradiction:
Improveprinting efficiencyVSAvoidheat accumulation
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The bonding material with protruding shape acts as an intermediary heat dissipation structure between the heat-generating resistor layer and the heat dissipation body. It provides an extended thermal pathway that facilitates heat removal from the resistor layer, preventing heat accumulation and maintaining printing quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces conventional thermal management approaches with a structurally-integrated heat dissipation solution. The protruding bonding material creates additional thermal conduction pathways without requiring separate cooling mechanisms, efficiently managing heat from closely-spaced heat-generating portions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 dissipates heat not contributing to printing and improves the durability of the thermal head by increasing the contact area between the bonding material and the underfill material, reducing the likelihood of peeling or breakage.

Implementation Method 1

effectively dissipates heat not contributing to printing

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a resistor layer having a plurality of heat generating portions... which generates heat by being electrified

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4129702B1Thermal head and thermal printer
Publication Date: 2025.05.21 KYOCERA CORP
  • EP4129702B1 patent drawingFigure 1
  • EP4129702B1 patent drawingFigure 2
  • EP4129702B1 patent drawingFigure 3

AI summary

A thermal head includes a substrate, an electrode, a bonding material, an electrically conductive member, and a sealing material. The electrode is located on the substrate. The bonding material is located on the substrate or the electrode. The electrically conductive member is located on the bonding material and is electrically connected to the electrode via the bonding material. The sealing material is located on the substrate and covers the bonding material and the electrically conductive member. The bonding material includes a protruding portion located at an outer circumferential edge of the electrically conductive member away from the substrate and the electrically conductive member.