Infrared (IR) — Grid
Glass or acrylic substrate, wrap-around-bezel frame, LED matrix
Principle of Operation
- LEDs create a grid of X and Y infrared light beams projected above the display and are detected by photo receptors on the opposite edge.
- Touch occurs when a finger or stylus blocks the beam from reaching light detectors.
- Controller’s constant X and Y axis scanning detects blocked light detectors and triangulates touch location.
Pros and Cons
|Functions with scratches and surface wear
|Solid contaminants, moving liquids or obstructions may cause a false touch and may create dead zones until completely removed
|Touch activated by bare finger, gloved hand, or a wide stylus
|Does not scale easily (new layout required)
|Transmission typically 90 % to 92 %
|Beam spacing limits accuracy and stylus width
|Touch occurs slightly above the actual surface resulting in possible touch parallax or an unintended touch response
|Requires a bezel design to house the LEDs and detectors
|Limited to two or three resolvable touches
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