SAW (Surface Acoustic Wave) touchscreen technology used in panel computers generates ultrasonic acoustic waves across the surface of a glass substrate. Transducers placed in the corners of the panel include transmitters (TX) that generate waves along the X and Y axes, and receivers (RX) that capture the signal after it has travelled across the entire surface. A grid of acoustic reflectors along the edges of the glass directs the waves along both axes. When the user touches the screen, their finger (or stylus) absorbs part of the acoustic energy - the controller detects this attenuation and precisely calculates the coordinates of the touch point.
A major advantage is the complete absence of any additional layers between the user and the glass - there is no film or resistive coating. As a result, the image is exceptionally sharp and bright, and the screen is highly responsive, reacting even to a light touch. This type of panel is also resistant to mechanical damage to the screen itself, even if the surface is scratched, touch functionality will not be affected.

The biggest drawback of SAW screens is their sensitivity to contamination and moisture. Dirt, dust, water droplets, or even work gloves can interfere with the acoustic waves and cause incorrect readings or complete loss of function. For this reason, the technology performs poorly in harsh environmental conditions, outdoor installations, or industrial settings. SAW screens also only respond to touch from a finger or soft stylus — they do not react to a hard, rigid object.

IR (Infrared) touchscreen technology works on a similar principle to SAW, except that instead of ultrasonic waves it uses invisible infrared beams projected across the entire surface of the glass. LED transmitters (TX) are placed along two edges of the frame, with photodiode receivers (RX) positioned directly opposite. Together they form a dense grid of horizontal and vertical beams. When any object interrupts two beams simultaneously (one horizontal and one vertical) the controller immediately reads the intersection coordinates as a touch point. Importantly, no additional material sits directly on the screen surface - the glass remains "clean", resulting in excellent brightness and image clarity, much like SAW screens.
IR technology requires neither electrical conductivity nor absorption of acoustic waves - it responds to anything that blocks light: a finger, a glove, or even a pen.

The biggest weakness of IR screens is their susceptibility to optical interference. Intense sunlight or strong artificial lighting can saturate the receivers and cause false readings or a complete loss of sensitivity. This makes IR screens less suitable for outdoor installations without dedicated shielding. Another drawback is the limited touch positioning resolution - the density of the grid is physically constrained by the number of LED emitters, so accuracy is inherently lower than that of capacitive screens. IR screens are also relatively thick due to the frame housing the transmitters and receivers, which makes miniaturisation more difficult. As for resistance to contamination, unlike SAW - where dirt merely weakens the signal - in IR screens even a small physical obstruction on the edge of the frame, such as a smudge or an insect, can completely block a beam and generate a false, permanent touch signal.