Touchscreen Technologies
Touch screens are used in many different areas of our day to day. They allow the ability to interact with active media presented typically by a display device like a monitor, phone, or tablet style screen. There are a few different technologies of touchscreens, each with their own advantages and disadvantages depending on their use case scenarios.
Resistive Touchscreens
Resistive was the most common type of early touch screen technology. It is a low-cost solution that can still be found in many touch screens, including consumer electronics and point-of-sale applications. The resistive screen is popular because of its relatively low price (at smaller screen sizes) and ability to use a range of input objects (fingers, gloves, hard and soft stylus).
HOW IT WORKS
A resistive touch screen uses a controller and a specially-coated glass overlay on the display face to produce the touch connection. The touch screen panel consists of two thin, electrically conductive layers separated by a narrow gap. When an object, such as a finger, presses down on a point on the panel’s outer surface, the two layers become connected and then cause a change in the electrical current, which is registered as a touch event.
CONSIDERATIONS
Versatility: Because resistive technology is based on pressure, you can use nearly any type of pointing device, including a finger (gloved or not), pen, or stylus
Accuracy: Resistive Touchscreens are highly accurate, particularly when used with a stylus since the touchscreen’s accuracy is a single display pixel. This makes it ideal for handwriting recognition and for working with small control elements.
Fewer Inadvertent Touches: Because they rely on pressure for activation, resistive touchscreens won’t typically register light touches, such as when liquids (such as rain) fall on the touchscreen.
Low Cost: Resistive touchscreens offer a more affordable alternative than other touchscreen options.
Infrared Touchscreens
Infrared touchscreens make up the majority of technology used in 32” or larger rental touch screen displays. Although there is an increasing number of displays as large as 65” that are beginning to use other technologies. Infrared technology relies on the interruption of an infrared light grid in front of the display screen. The touch frame contains multiple rows and columns of infrared LEDs and photo transistors, each mounted on two opposite sides to create a grid of invisible infrared light. Think of each row/column being similar to the sensor that you may trip when walking into a store or at the base of your garage door to safely prevent unwanted closure.
HOW IT WORKS
The bezel shields the electronics from the operating environment while allowing the infrared beams to pass through. The infrared controller sequentially pulses the LEDs to create a grid of infrared light beams. When a stylus, such as a finger, enters the grid, it obstructs the beams, one or more phototransistors detect the absence of light and transmit a signal that identifies the x and y coordinates.
CONSIDERATIONS
High Image Clarity: This makes the infrared touchscreen well suited for large displays.
Durability: Because touches are activated by the interruption of the infrared beam grid, the infrared touchscreen isn’t affected by scratches, fingerprints and other forms of minor damage.
Versatility: Infrared touchscreens can be activated with a bare finger, gloved finger, stylus and more.
Sensitivity: Infrared touchscreens are susceptible to erroneously triggered commands, for example, if a foreign object comes into contact with the screen. Dust and dirt build up can cause accuracy issues with the sensors. In some older or less refined systems direct lights aimed into the sensors can be an issue, although more recent units have had very little issues with lighting interference.
Projected Capacitive Touchscreens (P-CAP, PCT)
Also known as P-CAP, projected capacitive touchscreens are used in nearly all current mobile phones, tablets, laptops, and larger number of monitors under 32”, although monitors up to 65” and sometimes larger can also be found. P-CAP touchscreens can work with special gloves or stylus if needed as well.
HOW IT WORKS
P-CAP touchscreens are made up of a matrix of rows and columns of conductive material layered on sheets of glass. When the touchscreen is energized and a conductive object such as a finger comes into contact with the glass touch panel, it distorts the electrostatic field at that specific point. Even if the glass is scratched or broken it will still function properly (like when your phone screen protector is cracked, but the phone screen is not)
CONSIDERATIONS
Durability: P-CAP touchscreens are strong and durable. Functionality is typically not affected by dirt and fingerprint smudges. With no moving parts and no front coatings, projected capacitive touchscreens are extremely durable.
