Download Piezoelectric

Epson Piezoelectric Colour
Inkjet Printer
ECE 434 Presentation
Aurélie Barras
Jeff Emmett
Hannes Rose
Outline
 Introduction
 Product Definition
 Operating Principle
 Fabrication and Manufacture
 Packaging Principles
 Signal Transduction Technique
 Future Applications
Introduction
 Origin of piezoelectric effect: atomic arrangements
 Lack a center of inversion symmetry
able to create internal electric polarization
 Piezoelectric materials: quartz, tourmaline, gallium
orthophosphate, crystals of the CGG group, piezoelectric ceramics
 Useful for fast-response applications and for sensing or
generating vibrations
Introduction

Voltage applied:
I.
II.
III.
change in electric potential
change in the lattice structure
change in the physical dimensions of the material
F
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F
Product Definition
 Applications: reach from high end products for special purposes
to very cheap devices for private households
 Desired objectives: speed, cost effectiveness, high print
resolution and manufacturability
 Epson patent: Use of piezoelectric elements to expel ink
droplets from the print head one drop at a time
Operating principle
 Animation
Fabrication and Manufacture
● Silicon wafer 625 µm thick, oxidized to create layer of SiO2
● Insulating layer of zirconium oxide deposited by sputtering
Fabrication and Manufacture
● Common lower electrode of actuator device made of platinum and iridium
● Laminated on top of zirconium oxide and patterned appropriately
Fabrication and Manufacture
● Piezoelectric layer of lead zirconate titanate deposited through “solgel” method
 Sol-gel method: metal-organic material dissolved into solvent,
dried until gelatinous, then baked.
● Zirconium oxide layer prevents the lead components of piezoelectric
layer from diffusing into the elastic film layer
● Upper electrode of the actuator made of iridium and deposited on top
of the piezoelectric layer.
Fabrication and Manufacture
● Piezoelectric layer and the upper electrode are patterned into actuator
elements
● Layer of gold deposited over the entire surface, patterned using a resistive
mask to provide gold contacts
Fabrication and Manufacture
● Protective wafer of thickness approximately 400 µm attached to top of device
● Created from silicon for same coefficient of thermal expansion, although
glass, ceramic material, or metal could be used
● Vias in the protective plate provide a means to connect the contacts to a
driving IC or act as ink storage reservoir
● Provides additional tensile support to the substrate wafer
Fabrication and Manufacture
● Substrate wafer ground to a desired thickness of 70 µm
Fabrication and Manufacture
● Mask film of silicon nitride applied to the bottom of the substrate and
patterned
● Wafer subjected to anisotropic wet etching using hydrofluoric-nitric acid
Fabrication and Manufacture
● Etching produces the pressure generating chambers and the ink supply paths
Packaging Principles
 Protection from the environment
 Access to the environment
 Multi-chamber arrangement
Packaging Principles
 Six colours
 12 columns of nozzles
Signal Transduction Technique
Drive buffer
PE
Wave generator
Future Applications
 Manufacturing of colour filters
for LCDs or plasma screens
 Printing of ceramic materials
 Printing of electric circuits for
microsystems
 Production of biochips
 Food industry
Questions?