As a master inventor and director of strategic technologies for Lenovo’s Research and Technology team, Jamie Rutledge helps Lenovo’s consumer and commercial business teams navigate the plethora of touchscreen technologies and decide which ones make it into new products. Jamie explains his take on why more technology choice is a good thing. People often ask me: What’s the dominant touch screen technology (i.e. the most prevalent are optical, resistive, capacitive and surface wave) for the future? The simple answer is: There’s no clear winner! Here’s why. Each technology has a unique value proposition for the particular product.  We look at these “trade offs” based on the different ways people use PCs .

Let me give you an example. If we’re looking at the Lenovo C315 all-in-one desktop, the major use case is indoors in a home office environment for personal and family use. Because the PC resides in a typical desk environment, the touchscreen generally only requires one or two point (finger) input. Knowing this, the product team defines the right solution for a value product taking into account the large 20-inch screen PC. The touchscreen technology they select is very dependent on the PC’s screen size because the cost/function value depends on the surface area of the screen. For instance, placing capacitive ITO-like (indium tin oxide) materials over a large surface area is more expensive than using optical techniques for surface touch, so there’s a lot of value to using optical touch for indoor use on large screens.  In optical touch, two optical sensors and infrared light are used to determine the position of the touch input.

To contrast this, let’s look at the ThinkPad T410s laptop. Because the use case is different – it’s highly mobile - a different technology will most likely be used. The T410s has less volume for optical sensors (14-inch screen), and the laptop form factor is more likely to be used outside. The engineering teams then account for the possibility of higher amounts of ambient infrared light, which optical solutions don’t support. Taking into account all of these variables makes a case for using capacitive touch technology, which is similar to what’s used on smart phones today. Capacitive touch uses sensors  that are embedded below the surface (screen), and they interpret when the  electrostatic field is interrupted by a touch, using controllers to determine the position. In addition to optical and capacitive touch, resistive and surface acoustic wave are frequently used technologies. Resistive simply has two thin layers that when pressed together connects to form a circuit and registers the touch. Surface acoustic wave transmits a high frequency acoustic wave, and when the screen is touched, the frequency is disrupted. So what does the future hold for touchscreen technologies? I think all of the existing ones will survive because each holds a different value proposition. I will say there are other technologies on the horizon which we’re developing and supporting. The future holds an exciting ecosystem of natural human interaction that we’re involved in creating.