Tag Archive for: touch screen manufacturing

Q&A Session with Mil/Aero Sales Engineer James Hunt

What excites you most about diving into touch screen manufacturing?Mil/Aero Sales Engineer James Hunt
The touch screen industry itself is exciting because one can relate to the various applications in everyday life. Almost everywhere we go we encounter touch screens – supermarket, bank, doctor’s office, casinos, airport – the list is virtually endless.

In terms of touch screen manufacturing, it is interesting because every solution is different and comes with unique considerations and challenges. For the military, the important touch screen attributes are generally high optical performance and high reliability. Other segments require high volume and low cost. We encounter a wide array of needs and requirements that often vary by industry or application.

Another exciting aspect of Touch International right now is our improvement plan to the Austin facility. We have undertaken facility upgrades which include a new clean room, and are implementing processes to transfer our company into a lean organization which will ultimately better serve our customers.

What role do you see Touch International playing within the Mil/Aero market space?
Our role is not only to provide products to this market but also to help our customers find solutions throughout the concept, development, prototype and volume production stages. This process is even more important for the military/aerospace segment because of higher standards invoked on products from a reliability, performance, and traceability perspective. We see ourselves as a key custom solution supplier for these market segments.

Where do you think military electronics are headed in 2012 and beyond?
In terms of traditional military platforms, we expect to see some contraction in the electronics market. Having said this, Touch International does see opportunities in the existing platforms as well as new technologies being implemented in the same sector.

I do anticipate seeing a rise in the deployment of touch technology in military applications. Touch technology has proven itself to be highly versatile, and applications for touch screen devices are virtually countless. Although touch screen electronics have been in the mainstream for quite some time, military devices take a little bit longer to develop.

While there are many military applications for touch technology, one of the most obvious is the ability to communicate through mobile phones and touchpads. In recent weeks, US government agencies and contractors have publicized the development of secure software run on Android-based touch screen devices to be deployed to soldiers in the field. By providing soldiers with this kind of touch-enabled device, classified information containing the location of infantry or potentially dangerous areas can be sent directly to the soldier on a digital map.

This breakthrough is just one example of how touch screens are becoming a requirement in military electronics and provide key advantages in the field. Whether it is a large-format touch screen being used to view maps at a regional command post, or one of the thousands of hand-held devices used in the field for communication, or part of the control panel inside of an MRAP vehicle, the possibilities for touch technology in military electronics are virtually endless and will enjoy growth across the board.

What is Touch International working on right now in terms of military solutions?
The military is always seeking to have the best-trained soldiers, using the best equipment and the latest technologies to accomplish its mission. To that end, our goal is to provide award-winning touch screen and LCD enhancement solutions that meet these needs. In 2012 Touch International is focused on building sunlight readable displays with EMI shielding and a full bond to LCD solution; this solution provides optimal visibility in changing light conditions, noise suppression to remain undetected, and a ruggedized display to ensure accuracy even during challenging environments.

Can you please explain what sputtering and micro-etching are and how are they used in touch screen manufacturing to impact touch performance?

Sputtering and micro-etching are complimentary processes that are often used to reduce touch screen borders and package sizes and ultimately improve touch performance.

“Sputtering” (aka known as suck-and-spit by the inventor) is a process by which an opaque material, usually indium tin oxide (ITO) is put onto glass or plastic, in a vacuum, resulting in a transparent thin film (say, 300 angstroms [number of atoms] thick). This is the starting point for overlay-type touch screens. Today, we also sputter molybednium/aluminum/moly (MAM) over the ITO to make very fine conductive traces (next answer) so that the nutcase designers can have unreasonably tiny borders.

Micro-etching is a method of removing the ITO or MAM in the sub-50 micron line width. On the touch sensor, making the ITO etch lines so tiny that you cannot see them eliminates all shadows, making the image look great and enhances the magic of touch.

Because projected capacitive is a scanned system, there must be a low resistance connection to every ITO row and column, occurring every 6 millimeters or so, and adding up to about 30 electrical signal traces at the edge of the ITO. When the designer has allowed almost no area to make the 30 separate connections, the only way to do it is to use tiny lines micro-etched in the area at the edge of the screen, which is usually hidden by an opaque (black) border.

While micro-etching the transparent ITO is no more expensive than conventional etching, the semi-conductor class equipment is a very expensive capital acquisition which is amortized into the product.

You do not want to have tiny borders on your product unless there is no other option, because this second step is expensive. Normally a projected capacitive screen is made by micro-etching the ITO in the visible touch area. After this etching step, the glass is put back into the sputtering chamber and an opaque layer of MAM is coated over the top of the etched ITO. Then the metallic layer is micro-etched again to create the fine lines at the edge. While the iPhone has micro-etched borders, the iPad does not which helps control the cost.

There is an even more expensive way to make your projected capacitive part known as “SITO”, for single sided ITO, which requires three trips to the sputtering chamber and three trips through the micro-etch line…..but I am not going to say any more so as to not encourage you…….

Touch Guy