Conductive ink is a critical component in creating printed objects that conduct electricity. The inks themselves may be classified as fired high solids systems or polymer thick film (PTF) systems that allow for circuits to be drawn or printed on a variety of substrate materials. Typically, these inks contain conductive materials, including powdered or flaked silver or carbon-like materials. The membrane switch market has moved toward printing with conductive ink in the past several years because there is such little waste associated with the process and consumers demand smaller electronic devices. However, there are changes that can be made in choosing conductive inks to improve the membrane switch market.
Conductive Ink Is Responsible for More Advancements in Printed Electronics
Thanks to conductive ink, advancements have been made in printed electronics that have allowed for industry growth at an exponential rate in recent years. Improvements in printing techniques, equipment, and materials have resulted both in more efficient production of existing electronics and in the development of new, innovative applications.
Other benefits to the membrane switch market as a result of conductive ink include: replacing conventional electronic components with more compact and lighter solutions; reduced manufacturing costs; improved component performance, reliability, and increased environmental resistance; and new, unique applications. Similarly, screen printing continues to be an important part of the electronics manufacturing process, specifically in printing graphics for membrane switches, touch screen overlays, and PCB legend text. Overall, conductive ink has had a very positive impact on the membrane switch market.
Conductive Ink and Membrane Switch Market Trends
Marketing reports show that the conductive ink market is expected to grow over the next few years to reach $3,660 million by 2018. Conventional conductive inks continue to dominate the market, as these are used in membrane switches. The Asia-Pacific leads consumers of conductive inks and will most likely lead the market in the future because of its large photovoltaic manufacturing. The reason for the growth in the conductive ink market is due to the increasing demand for efficiency and miniaturization of consumer electronics.
As consumers want smaller, more advanced electronic devices, the demand for conductive ink increases because it is a necessary component in replacing bulky, energy-consuming wires and circuits. Thus, the membrane switch market will grow as membrane switch designers and engineers develop the smaller devices that are more energy efficient and more durable than those that contain traditional wire circuits.
Conductive ink also impacts the types of substrates used in the design of printed electronics systems. Deciding between paper, plastic film, metal, or another material is a large focus of the membrane switch market, which traditionally leans toward polyethylene terephthalate (PET). PET typically resists tearing and humidity when compared to paper and is cheaper than polyimide (PI). As different types of conductive inks are developed, especially those that bond differently to PET, the membrane switch market may shift as testing and reliability of the conductive ink progresses.
Conductive Ink and the 100-Ohm Barrier in the Membrane Switch Market
Alan Burk, Membrane Switch News Editor, claims that there is an unwritten understanding that 100 ohms is the maximum circuit resistance membrane switch engineers should build into their products. This “low level of circuit resistance was made possible through the availability of highly conductive silver inks with volume resistivities of 0.03 ohms/square/mil or less.” Yet, the inks can be quite expensive and add to the cost of a completed switch, thereby negatively impacting the membrane switch market in two ways. First, membrane switches remain at the 100 ohm barrier. Second, membrane switch designers and engineers are leery of using the expensive silver inks.
Burk mentions a conversation he held with an electronics designer who was working on a project with a small numerical keypad switch. The switches he received worked well and had an average circuit resistance of approximately 20 ohms. But, after looking at the circuit design, the engineer realized the actual circuit resistance could be as high as 2500 ohms before affecting switch performance.
The actual resistance in this particular instance could have been 100 times higher, had the membrane switches been made with a less expensive conductive ink with a higher volume resistivity. This is a perfect example of how fixed the membrane switch market is at the 100 ohm barrier, and how the market could be more economical if more manufacturers would switch to the higher-volume resistive inks with lower cost.
Obviously, the cost of membrane switches is greatly affected by the cost of the conductive ink used. So, Burk recommends that in order to be more economical, the membrane switch market needs to be able to determine the maximum resistivity of ink required to meet customer requirements. Again, the higher the resistivity of the ink, the lower the cost. Thus, membrane switch manufacturers need to stop accepting a general answer of 100 ohms for maximum switch resistance requirements.
Burk concludes by suggesting that it is time to look at alternative methods and materials for switch production, since competition among membrane switch manufacturers continues to escalate. The first step is in looking at conductive ink alternatives and checking into silver- and carbon-based conductive inks that have volume resistivities of 0.008 ohms/square/mil and up. The thing that membrane switch manufacturers need to keep in mind is that the higher the volume resistivity, the fewer silver particles the ink contains. The key to a wider membrane switch market is to forgo the 100-ohm switch resistance limit.
Overall Impacts of Conductive Ink on the Membrane Switch Market
The membrane switch market already has been positively impacted by conductive inks and advancements in their capabilities. Conductive ink literally changes the shape and nature of membrane switches, which impacts the membrane switch market. Consumers are driving the market, in part because of their demand for smaller, more efficient electronic devices. The membrane switch market has grown, and is projected to continue to grow, because of the advancements in conductive ink. As long as membrane switch designers and engineers open themselves to all of the possibilities afforded by newly formulated conductive ink, the membrane switch market will most likely thrive for quite some time.
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