Digital Fabrication Alaska

 

I started the day in the Digital Fabrication conference at a session devoted to Industrial and Commercial applications. This was a great opportunity to take a look at some real applications happening now. This session contained 4 sessions featuring some very different technologies but interestingly all using inkjet.

 

The first paper examined alignment issues for multilayer fabrication by inkjet. Both single sided and double sided coating of a substrate was covered together with a machine vision system to monitor registration. The author was achieving + 5 microns placement accuracy between layers on the same side of the substrate with a few extra microns tolerance between the two sides. Not bad!

 

The second paper described a rather novel fabrication technique for silicon solar cells. Although this was a photovoltaic application I imagine that this method could find application elsewhere in printed electronics. They used inkjet printing technology to jet a plasticiser onto a resist layer. This makes these areas of the resist permeable to an etching solution allowing the formation of openings to the underlying layer for metal contacts. This method also has the intriguing possibility that these steps can be repeated, generating multiple contact patterns.

 

The third paper was a good example of a manufacturing solution where device fabrication incorporated into a packaging line is an interesting option. A sensor has been designed that is inkjet printed and exhibits a colour change depending on the environment. Although this sensor is designed to be used as is for applications such as food packaging it could be envisaged that this could become an enabling technology for a printed electronics sensor in conjunction with OLED elements for electronic systems.

 

The final paper described roll to roll inkjet printing of a cholesteric liquid crystal display. The system is currently capable of fabricating a colour display of a size suitable for a mobile application.

 

While my afternoon was devoted to the Security and Forensic Printing session I managed to sneak out to see two rather interesting papers in the Media for Digital Printing session.

 

The first dealt with surface modification of a substrate designed to receive toner. The interesting part to this paper is that methods to modify the surface structure of the substrate were described. This is an unusual system in that it uses a multilayer substrate more commonly associated with inkjet products, which is a technology that I believe is essential for some future advanced fabrication applications. The second paper continued this theme but this time describing a multi-layer inkjet product. In this case it described the optical properties of the product - a technology that is good to have in the toolbox for some high end printed display applications.

 

The Security and Forensic Printing session took up a full afternoon with six papers. This is an applications area where I see a great future for a hybrid of conventional printing and printed electronics, an area that featured strongly in my tutorial on the previous Sunday. It was exemplified rather well by the first speaker who cast security printing not as a technology but as an ecosystem. It could equally well be described as a journey where each individual technology introduced is but a stopping point. As the counterfeiters catch up it is time to move on to another technology. By combining conventional printing with printed electronics we create security ecosystems that are more difficult to duplicate and easier to validate.

 

Subsequent speakers gave examples of various printing techniques that enhance product security, including examples of the science of stenography. This is a technique to hide information in images - a learning point for printed displays in security applications?

 

The final speaker presented some work on the use of conductive inks in variable data printing processes. Conductive inks raise the possibility of reading the data in several different ways such as machine vision, human readable and conductor contact. I found this particularly interesting for several reasons. First, it showed some early work on conductive inks for fibrous and non-porous surfaces. I have an interest in fluid / substrate interactions and I believe that fibrous substrate capability is a very useful one for the toolbox. Second, I lecture elsewhere on Image Science and there were some interesting facets of multi-modal reading that look worthy of further exploration as we move to hybrid applications.

 

This was also the second day of the exhibition. A wide variety of companies exhibited this year and I found it useful to get a snapshot of the technologies on offer. The exhibition hall certainly seemed busy whenever I called in. The exhibitors seemed well satisfied with the interest being generated and given the quality of the audience attracted by these conferences I feel sure it will have been a worthwhile visit for them.

 

At the end of a long day we had the conference reception, held at the Anchorage Museum of History and Art. A stunning venue holding some fascinating pictures provided the backdrop for one of the best networking events of the conference.

 

 

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