Low Profile Encapsulation for Bonded Wires in Thermal Inkjet Printers

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Solution Overview

Problem

Conventional film encapsulation processes for thermal inkjet printers are complex, prone to peeling, and harbor trapped air, making it difficult to maintain a low profile encapsulation height near print head nozzles, which interferes with servicing and print quality.

Innovation Solution

A low profile encapsulation method using a bonded wire with a truncated shape formed by compressing or guiding the encapsulation material, ensuring the encapsulation height remains under a hundred microns, allowing closer proximity to print heads without interference during servicing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional film encapsulation process is used, then encapsulation can be applied, but the encapsulation height becomes too high and the process becomes complex

Engineering Contradiction:
Improveencapsulation height controlVSAvoidencapsulation process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the physical state of encapsulation material from liquid film to solid bead form, fundamentally altering how the material is applied and shaped. This parameter change enables precise height control through bead size selection rather than complex film deposition processes

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses disposable encapsulation beads that are placed once and then consumed/processed, eliminating the need for complex reusable film deposition equipment and multiple processing steps. Each bead is a self-contained encapsulation unit

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Length of stationary object

If film encapsulation is used to reduce height, then encapsulation height decreases, but peeling and trapped air issues occur

Engineering Contradiction:
Improveencapsulation heightVSAvoidencapsulation stability
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The patent changes the morphology of encapsulation material from thin film to spherical bead with controlled size parameters. This allows the bead to be compressed into a flat pancake shape that maintains structural integrity while achieving low height, eliminating peeling and air trapping issues

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The encapsulation beads are pre-formed with controlled size and properties before placement. This preliminary preparation ensures that when compressed, they achieve the desired low profile shape without introducing defects like air pockets or peeling edges

Inventive Principle:
Principle #10Preliminary action

3Length of stationary object

If encapsulation height is reduced to under hundred microns, then low profile is achieved, but servicing interference occurs

Engineering Contradiction:
Improveencapsulation heightVSAvoidprint head servicing
Core Design Contradiction:
Length of stationary objectVSEase of operation

Solution Approach 1:

The patent creates local variation in encapsulation shape by compressing the bead into a pancake form with specific dimensional characteristics. The encapsulation has low height in the vertical direction (under 100 microns) while maintaining adequate lateral coverage, providing local optimization for both low profile and servicing access

Inventive Principle:
Principle #3Local quality

4Area of stationary object

If encapsulation material is deposited to sufficient amount at base, then coverage is adequate, but height increases and interferes with servicing

Engineering Contradiction:
Improveencapsulation coverage areaVSAvoidencapsulation height
Core Design Contradiction:
Area of stationary objectVSLength of stationary object

Solution Approach 1:

The patent uses spherical encapsulation beads as the starting form, which when compressed become pancake-shaped with curved edges. This geometric transformation allows the material to spread laterally for adequate coverage while the compression controls the vertical height, resolving the contradiction between coverage area and height

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

The method allows for a compact and reliable encapsulation that prevents interference with print head servicing, reduces trapped air issues, and enables more compact printer designs by maintaining a low encapsulation height, enhancing print quality and reducing manufacturing complexity.

Implementation Method 1

the encapsulation material is compressed to form a truncated shape

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3063008B1Encapsulating a bonded wire with low profile encapsulation
Publication Date: 2020.10.07 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3063008B1 patent drawingFigure 1
  • EP3063008B1 patent drawingFigure 2
  • EP3063008B1 patent drawingFigure 3~4

AI summary

Encapsulating a bonded wire with low profile encapsulation includes applying encapsulation over a bonded wire that is connected to a die on a first end and to a circuit component on a second end and truncating a shape of the encapsulation to form a truncated shape.