Frustrated Total Internal Reflection (FTIR)

Sensor Materials

Projection Surface, Silicone Rubber, IR LED, Acrylic, Camera

Principle of Operation

  • A contact (finger/blob/tag/object) is placed on the display
  • The light rays are frustrated, since they can now pass through into the contact material (usually skin layer on top of the glass or acrylic plane), and the reflection is no longer total at that point.
  • This frustrated light is scattered downwards towards an infrared webcam, capable of picking these ‘blobs’ up, and relaying them to tracking software.

Advantages

  • Full Multi-touch capabilities including advanced gestures
  • Multi-user collaboration potential
  • Fine detail touches can be recognized

Disadvantages

  • Sensitive to ambient light
  • Required on site calibration
  • Requires a compliant surface coating (silicone rubber), sensitive to wear and scratches - no glass surface
  • Cannot recognize objects or markers