Infrared Touch Technology  Infrared touch screens operate on the basis of light-beam interruption, commonly referred to as beam break, to determine the location of touch events. Strengths Can be used with gloved or wet hands Last long and are durable because there is no need to apply pressure Scales with perimeter and not area Have high clarity as there is no requirement for multiple layers or patterning on the screen Can use a protection glass in front the TFT panel Cost Effective Weakness Cannot distinguish between user input or foreign objects like mud or insects crawling on the screen Can be accidentally activated due to dust and humidity Response times are slow as the operation is CPU intensive Projected Capacitive -PCAP Excellent readability – light transmission of up to 91% through a standard sensor Rugged vandal resistant construction, Ideal for internal and external usage – a proven solution for public access areas Excellent optical clarity – the sensor can be enhanced with optical coatings and filters Accuracy – less than +/- 1.5% of reported position Response time – < 20ms Stability – no drift, therefore no recalibration is required Pointing device – works with gloved and ungloved finger Immunity to damage – unsurpassed impact, vandal, and scratch resistance External environments – unaffected by dirt, moisture and rain Operating temperature – ranges from –35ºC to +70ºC. Sub zero operation may be enhanced by an integrated heater panel Resistance to contamination – unaffected by harsh cleaning fluids Shielded filters can be specified Supports both RS232 and USB Embedded controller – further enhances reliability and life expectancy Operating systems supported – Windows® 9X, NT, ME, 2000, XP, XPe, Vista, Windows® 7, 8 & 10 (single, dual & multi touch), Linux and Android Advantages: Excellent image clarity More resistant to scratching than surface capacitive touch screens Resistant to surface contaminants and liquids- dust, oil, grease, moisture Multi-touch (up to 40 touch points) Disadvantages: Sensitive to EMI/RFI Must be activated via exposed finger, thin surgical or cotton gloves, although some PCAP windows (like those used by AbraxSys) can be triggered by a heavy gloved hand Surface Acoustic Wave Touch Technology – Surface Acoustic Wave (SAW) touch screens work by using ultrasonic waves to detect touch events and the location of the user’s input. They operate in a similar way to beam break technology. Like optical touch screens, the technology is also perimeter based, with the only difference being that sound waves are used instead of light. Strengths Have very good visibility because of a single glass layer Are very durable and can work even when the glass panel is scratched Are resistant to electromagnetic interference as acoustic waves are used to determine the location of the input Relatively Cost Effective Weakness Does not support Multi Touch as Infra-Red and PCAP Cannot be protected with a front Anti Vandal Glass Will not work with materials like pens that do not absorb ultrasonic waves Can malfunction in the presence of foreign materials like water or oil droplets which can absorb the waves Attract dirt, water and impurities in the bezel area as the perimeter cannot completely be sealed off from the environment because transducers need to send and receive waves Resistive Touch Technology There is an air gap between two layers of transparent material. When the user applies pressure to the outer layer, it touches the inner layer at specific locations. An electric circuit is completed and the location can be determined. Though they are cheaper to build compared to capacitive touch screens, they are also less sensitive and can wear out quickly. Strengths Inexpensive to make Can accept an input from anything, including pens, gloved fingers etc Can be easily assembled from the component parts; screens and sensors Can work in rain or in the presence of other fluids Cost Effective Weakness Does not support true multi touch Is not very sensitive and excessive force is needed for touch activation Distortion in electric field between layers can cause errors in touch detection Has an air layer between the two glass layers which affects display quality and clarity Not scalable as it is impossible to maintain uniform thickness between two screens beyond a certain size, and the ITO deposition technology hits a performance ceiling beyond 22” Outer layer scratches easily, and the ITO layer cracks with use, resulting in dead zones Touchscreen Sensors and Industrial Touch Monitors ©