Which Touch Screen Is Right For You?

What types of touch screens does Thinlabs provide? How do they work? What are the advantages and disadvantages associated with each?

Which Touch Screen is Right for You?
  5-Wire Resistive Infrared Project Capacitive
Clarity Good Very Good Very Good
Price $ $ $$$
Touch Type Single Dual Multi
Activation Bare finger, stylus,
work glove, surgical glove
Bare finger, stylus,
work glove, surgical glove
Bare finger, stylus,
surgical glove
Sensitivity Good Very Good Very Good
Calibration Very Good Very Good Very Good
Accuracy Very Good Very Good Very Good
Scratch Resistant Poor Very Good Very Good
Industries Restaurants, Industrial Medical, Retail,
Restaurants, Industrial
(non-greasy environments)
Digital Signage, Gaming,
Industrial, Medical,
Retail, Kiosks
Sensitivity to:      
Cleaners Very Good Best Best
Dirt Best Good Very Good
Vibration Best Best Best
Ambient Light Good Best Best

Resistive

“A resistive touch screen panel comprises of several layers, the most important of which are two thin, transparent electrically-resistive layers separated by a thin space. These layers face each other with a thin gap between. The top (touched) screen has a coating on the underside surface of the screen. Just beneath it is a similar resistive layer on top of its substrate. One layer has conductive connections along its sides, the other along top and bottom. A voltage is applied to one layer, and sensed by the other. When an object (such as a fingertip or stylus tip) presses down onto the outer surface, the two layers touch to become connected at that point: The panel then behaves as a pair of voltage dividers, one axis at a time. By rapidly switching between each layer, the position of a pressure on the screen can be read.

Resistive touch is used in restaurants, factories and hospitals due to its high resistance to liquids and contaminants. A major benefit of resistive touch technology is its low cost. Additionally, as only sufficient pressure is necessary for the touch to be sensed, they may be used with gloves on, or by using anything rigid as a finger/stylus substitute. Disadvantages include the need to press down, and a risk of damage by sharp objects. Resistive touchscreens also suffer from poorer contrast, due to having additional reflections from the extra layers of material (separated by an air gap) placed over the screen.”1

Projective Capacitive

Projected Capacitive Touch (PCT or PCAP) technology is a variant of capacitive touch technology. All PCT touch screens are made up of a matrix of rows and columns of conductive material, layered on sheets of glass. This can be done either by etching a single conductive layer to form a grid pattern of electrodes, or by etching two separate, perpendicular layers of conductive material with parallel lines or tracks to form a grid. Voltage applied to this grid creates a uniform electrostatic field, which can be measured. When a conductive object, such as a finger, comes into contact with a PCT panel, it distorts the local electrostatic field at that point. This is measurable as a change in capacitance. If a finger bridges the gap between two of the "tracks", the charge field is further interrupted and detected by the controller. The capacitance can be changed and measured at every individual point on the grid (intersection). Therefore, this system is able to accurately track touches.

Due to the top layer of a PCT being glass, it is a more robust solution than less costly resistive touch technology. Additionally, unlike traditional capacitive touch technology, it is possible for a PCT system to sense a passive stylus or gloved fingers. However, moisture on the surface of the panel, high humidity, or collected dust can interfere with the performance of a PCT system.”1

Infrared (IR)

“An infrared touchscreen uses an array of X-Y infrared LED and photodetector pairs around the edges of the screen to detect a disruption in the pattern of LED beams. These LED beams cross each other in vertical and horizontal patterns. This helps the sensors pick up the exact location of the touch. A major benefit of such a system is that it can detect essentially any input including a finger, gloved finger, stylus or pen. It is generally used in outdoor applications and point of sale systems which can not rely on a conductor (such as a bare finger) to activate the touchscreen.

Unlike capacitive touchscreens, infrared touchscreens do not require any patterning on the glass for increased durability and optical clarity of the overall system. Infrared touchscreens are sensitive to dirt/dust that can interfere with the IR beams, and suffer from parallax in curved surfaces and accidental press when the user hovers his/her finger over the screen while searching for the item to be selected.”1

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Thinlabs customers can choose from 5-Wire Resistive, Infrared, and Projected Capacitive Touch Systems in a variety of sizes (from 15” to 42”) and models, including our HELIOS touch screen computers, Industrial All-In-One systems, and Digital Signage offerings. Additionally, systems are also available with optional conformal coating for heavy-duty, rough-and-tumble environments, plus an optional IP65 Compliant Front Panel for complete protection from dust and other non-corrosive materials; and enclosure protection from nozzle-projected water from any direction.

Contact a Thinlabs representative today for more information on of our current product offerings!

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Credits:
1.  Source:  Wikipedia