Exploring Mobile and Embedded Computer Solutions

Resistive vs Capacitive Touchscreens – Which Will Fit My Needs?

Resistive vs Capacitive Touchscreens – Which Will Fit My Needs?

Very few computer systems come without touchscreens these days. Whether it’s a simple interactive kiosk somewhere, a tablet, or even a full desktop computer, odds are good that users will be able to interact wit hthe system by touching appropriate areas on the screen.  However, when designing a new product or planning to purchase new products, designers and electronics manufacturers may offer you a choice you’re not entirely familiar with. “Capacitive” or “Resistive” touchscreens. What is the difference between these two technologies? Where is one or the other preferred? And how do you choose for your product? Fortunately, Estone Technology has the answers.

Capacitive Touchscreens – The Screen You Know

Capacitive Touchscreen Diagram

Sensors detect the amount of static capacity across multiple points to determine the focus of a touchpoint.

Your cell phone, tablet, and most of the technology you interact with daily probably uses a capacitive touchscreen. These touchscreens are extremely durable, support multiple touchpoints (often 10 or more at a time), and typically have a long life-cycle. The touchscreens are typically very thin, creating the effect that users are actually touching the icon, character, or other display item, rather than touching “through” glass.

Both Surface Capacitance and Projected Capacitance touchscreens are available, though Projected Capacitance has become the dominant technology as manufacturing processes have improved and costs have come down. In this technology, a thin, transparent conductive film detects disruptions in a static field created by other close-by objects, and interprets those disruptions as points of contact, or touches. Because that film is hidden beneath protective glass, and because the points of contact are all “virtual”, and because there are no moving or mechanical parts, capacitive touchscreens are often preferred for devices that will be subjected to physical abuse, including drops, scratches, and impacts.

The negative to this technology is that only objects that offer the proper static charge interference can be used to interact with the touchscreen. Typically, this takes the form of a bare finger, but this restricts usage in cold or hazard environments where gloves are necessary, and also restricts usage by handicapped individuals like amputees, or in naturally high or low static environments. Manufacturers have attempted to overcome this issue by including features like capacitive stylus pens, but such devices may be hard to use with gloved hands or by the handicapped, and may be easily lost.

Fortunately, if extreme environments or other challenges might make a capacitive touchscreen difficult to use for your product, there is an alternative.

Resistive Touchscreens – The Screen You Don’t Know

5-Wire Resistive Touchscreen

Based on the current resistance experienced from each of the four corners, the exact touch point can be calculated.

When people hear the term “Resistive Touchscreen”, they often aren’t sure of what’s being described. They sometimes think of very old monochromatic touchscreens that required a user to tap quite hard on a particular object to select it. Fortunately, that technology has nothing in common with a modern resistive touchscreen.

Resistive touchscreen technology eliminates the need for a static field. In both traditional 4-wire and newer 5-wire setups, overlapping grids of invisible conductors under a slightly flexible surface detect points where they are compressed together by pressure to create a circuit. Like capacitive screens, resitive screens have exceptional durability, though may be susceptible to sharp object impacts, since they need to be very slightly flexible. Some implmentations also suffer from glare, due to multiple layers between the user and the image on the screen, though various films and surface glass treatments reduce this.

The benefits of a resistive touchscreen versus capacitive vary based on the needs of the user. Resistive touchscreens can be used by gloved fingers, pens, styluses, prosthetic appendages – anything that can apply the necessary light pressure to the screen. They are extremely unlikely to be susceptible to any false inputs, since it is necessary to touch the screen to make an input. They also work well even when wet, dirty, oily, or dusty – circumstances that may prevent a capactive touchscreen from being used.

So Which Is Right For Me? Are There Other Touchscreens?

There are a number of other touchscreen technologies from the past and just now emerging – some of them you probably once interacted with, and others you probably will in the future. Technologies like Microsoft PixelSense (Surface) have a chance to revolutionize what a computer is and how we interact with it. But in the meantime, these two technologies are, and will continue to be, the dominant methods.

For your own product, consider how individuals will interact with it. Will they be indoors, or out in the elements? Will they need to wear special or protective gear while using it? Is glare an issue, or does the screen’s image quality need to be the absolute best possible? Will it need to be used in wet or dirty environments? Estone Technology can help you answer these questions for your tablet or touchpanel PC project. Contact us today to begin your discovery.

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