Which Touch Screen Is Right For You? - Thinlabs
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 17” 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
Projected Capacitive technology (more commonly referred to as PCAP) is the new kid on the block when it comes to touch technology. It is the same technology though that is used in smartphones and tablets due to its high levels of accuracy and speedy response times. The way PCAP touch technology works is by fixing a sensor grid between a layer of cover glass and the LCD panel, so when a finger touches the glass the grid detects the coordinates of the touch point. This is shown in the diagram below.
With this type of technology no recessed bezel is required and has a strong tempered edge-to-edge glass front for a more striking display. From easy cleaning to smooth gesture recognition PCAP is the definitive touch technology. This however comes at a cost as PCAP touch screens can be up to 60% more expensive than their Infrared counterparts.
Infrared touch technology (also known as IR) is the most widely used touch screen in commercial applications and has been the industry standard for decades. Using IR technology means that no actual contact with the screen is required so less damge is incurred over time. It works by embedding LED lights and sensors into the bezel of a monitor above the glass. These LED’s beam a signal across to the corresponding sensor on the other side forming an invisible grid. When the grid is broken by a finger, or other solid object, the sensors can detect the touch point. This is shown in the diagram below.
A bezel will always be required when IR is used due to the way it works. There is no chance of edge-to-edge glass being used with IR. However unlike PCAP, IR technology can scale to very large sizes with no drop in quality. From our Infrared Wall Mounted range, the Infrared Freestanding and Infrared Kiosks to our Interactive touch Displays which also use IR touch technology.
PCAP and Infrared are the two most suitable forms of technology used in commercial touch screens.
Both are great but depending on the customer’s requirements one may be more suitable than the other.PCAP is the touch technology of the future but it does come at a larger upfront cost. Infrared is the tried and trusted staple of touch technology. If you are looking for a more budget friendly touch screen then I suggest choosing an Infrared touch screen. If you are willing to invest then a PCAP touch screen will be worth every penny. There is no right or wrong answer when it comes to picking between the two; it is simply a matter of suitability.