There are various types of touch technology available on the market today, each functioning in a slightly different way and offering different advantages. In order to meet a diverse range of requirements, at Sharp/NEC we offer a wide selection of interactive displays using different technologies to best cater to various applications and customer needs.
Independent from the touch technology, using a zero-bonded or optical bonded glass, reduces the parallax effect and results in a more accurate and natural writing experience. The parallax effect describes the refraction angle of light which makes the physical location of a pen or finger on the glass appear to be different from the corresponding point on the LCD, depending on your line of sight.
Here we explain the different types of touch technologies
- Infrared (IR) Touch: The infrared touchscreen works by detecting interruptions of infrared beams emitted by LEDs embedded in the frame around the display. There are two rows of IR LEDs which generate horizontal and vertical invisible IR beams to form a large beam grid that covers the surface of the overlay. As soon as an object (e.g. finger or stylus) touches the surface, it blocks out the light beams. Photodetectors sense the interruption made by this object to localise the x and y coordinates and sends a signal to the processor to respond with the relevant action.
- Advanced IR (PrecisionTouch): Advanced IR is an evolvement of basic Infrared touch. Major manufacturers have brought their own advanced infrared touch versions to the market with varying degrees of improvements. At Sharp/NEC we call it PrecisionTouch. PrecisionTouch comes with upgraded light-emitting diodes (LEDs) and receptors embedded in the bezel around the screen. The biggest difference from basic IR is that the infrared light emitted from a single diode is picked up by multiple receptors on the opposite side of the display, greatly increasing the accuracy with which touch points are detected. The distance between the light beam structure and the glass is also decreased, minimising the height at which touch is activated.
- InGlass Touch: InGlass? is an advanced and improved IR-based touch technology developed by FlatFrog, a Swedish pioneer in innovative interactive technologies. Optical emitters and detectors around the edge of the display create a light fan-grid in front of the screen. Sampling based on proprietary InGlass? scanning algorithms allows tiny disturbances to be created on the surface by an object which are immediately detected by the receivers. Proprietary image reconstruction algorithm determines all touch and pen coordinates in real time leading to a no-lag experience.
- PCAP (Projected Capacitive) Touch: PCAP touch technology, unlike IR-based technologies, works from under the display glass. Conductive sensors underneath the touchscreen glass detect touch with the help of electric circuits. As PCAP technology detects electrical charges, you can use anything conductive to write on the touchscreen, including your fingers. When using a pen, PCAP touch displays require a special conductive passive pen or an active pen.
