Roller-based techniques and tools can now fabricate active electronic components as well as their interconnection.
When we hear the word “printed” in an electronics context, it’s natural to think first of the rigid, resin-based printed circuit board that has been the foundation of electronics designs for decades. Now, however, the term can describe another method of electronic device fabrication, one using roller-based techniques and tools more typically associated with printing magazines and newspapers, that can include fabrication of active components as well as their interconnections.
The recent demonstration of a printed electronic label illustrates the potential for this alternative approach. The label implements a self-powered, interactive smart sign such as might be used retail applications (Figure 1). It contains three main printable electronics technologies: a power source, energy storage, and a display, along with a membrane switch. Power comes from the Epishine printed photocells that are optimized for efficiently harvesting energy from indoor lighting. That energy gets stored in a printed battery developed by Evonik so that a printed electrochromic display from Ynvisible can operate on demand.
Figure 1 This self-powered electronic sign is merely a teaser for what can be done with printed electronics. Source: Epishine
The demonstration device is simple. The user presses the printed membrane switch to activate the dynamic display, which cycles through a pre-programmed animation sequence to draw the customer’s attention. But it’s easy to see how this basic foundation can be augmented with more powerful capabilities.
An RFID device could be incorporated after the printing process, for instance, to provide generic signage with the ability to be updated, such as customizing the label’s wording and price display. Similarly, a sensor and microcontroller could be added to make a self-powered temperature display that returns archived data to an RFID scanner upon demand. With proper energy management, that same design basic could also be configured as an IoT device that could periodically report its data wirelessly to a local hub.
The key here is that the device’s foundation – power, interconnect, and display – are all printed in much the same way as a newspaper. Thus, the device’s basic structures can be produced in large quantities at high speed, hence low cost. The resulting devices will also be quite flexible to be shaped to match curved surfaces without any additional manufacturing steps.
The three technologies behind this demo device are not the only types of printable electronics available. Members of the Organic and Printed Electronics Association (OE-A) have put a wide range of additional electronics technologies on offer, including transistors, passives, interconnect circuits, sensors, light sources, antennas, and touch surfaces. Even flexible, although not printed, integrated circuits are possible with technology from PragmatIC Semiconductor. Printing can be performed on a variety of substrates, including plastics and fabric.
Much of this technology has been under research and development for more than a decade, but now it is reaching production availability. Further, the printed electronics industry has grown to a size that it is able to support a specialized trade show. The LOPEC Conference is being offered online this week and can provide developers with access to numerous vendors and manufacturers working in the printed electronics field.
For some applications, the physical and design flexibility that printed electronics can provide is already available. For others, that availability is not far away. In any case, the approach provides a complementary alternative to traditional rigid circuits, which will open up a whole new range of design opportunities for developers.
This article was originally published on EDN.
Rich Quinnell is a retired engineer and writer, and former Editor-in-Chief at EDN.