Infrared touch screens operate on the basis of light-beam interruption, commonly referred to as beam break, to determine the location of touch events. They are perimeter based but differ from other perimeter based technologies such as Surface Acoustic Wave, in that they use infrared light beams and not ultrasonic waves.
In infrared touch screens, Light Emitting Diodes (LEDs) are placed on one side of the bezel and light sensors are placed on the opposite side in a one-to-one ratio. As an object touches the screen, it interrupts the light-beam causing a loss of light at the sensor. This loss of light is used to determine the location of the touch event. The LEDs and sensors are laid out in a grid so that each touch event breaks two beams, giving an X and a Y coordinate. These two coordinates are then correlated to determine the location of the touch occurring on the screen.
Pros of Infrared Touch Screens
The Baanto ShadowSense Advantage
Infrared touch screens have a number of issues that can impact their performance. ShadowSense touch screens are similar to infrared touch screens in as far as both use infrared light and both have sensors and emitters set into the bezel of the screen, however, that is where the similarity ends. ShadowSense has significant advantages over conventional infrared touch technology.
|Cons of IR Touch Screens||ShadowSense Benefits|
|Can be accidentally activated due to high ambient light||Built-in notch and band pass filters make the sensors immune to other sources of light except the embedded LEDs|
|Larger panels can suffer from lower resolutions due to high production costs, resulting in “staircase” position detection||Screens have native touch resolution of 4096×4096 regardless of size, and offer sub-pixel resolution on a 4K or UltraHD monitor|
|Multi-touch accuracy suffers as the IR beam pattern is spaced out||Screens can accurately place multiple objects to within 2 mm|
|Cannot distinguish between user input or foreign objects like mud or insects crawling on the screen||Screens can be configured to accept or reject touch events based on size, shape, transparency and frequency of impact|
|Response times are slow as the operation is CPU intensive||Does not require drivers or CPU to run, making response times near real time at 6 to 8 ms|
|Can deliver false responses if the user’s finger hovers before touching the screen||Can detect and ignore hovers and false touches|