Patent ID: 8872801

Claim:
A touch-sensitive apparatus for determining a location of at least one object on a touch surface, the touch-sensitive apparatus extending in a direction of depth and comprising: a light transmissive panel that defines the touch surface; a display arranged, in the direction of depth, behind the light transmissive panel and configured to present an image that is visible through the light transmission panel; a first compartment arranged, in the direction of depth, behind the display and including a light emitter arrangement configured to emit light to be introduced into the light transmissive panel for propagation by internal reflection in the light transmissive panel; and a second compartment arranged, in the direction of depth, behind the display and including a light detection arrangement configured to receive light that has propagated in the light transmissive panel; and a light blocking sheet that is arranged between the first compartment and the second compartment, wherein the light blocking sheet is parallel with the touch surface, and the second compartment is separated from the first compartment, such that light emitted from the light emitter arrangement is prevented from reaching the light detection arrangement without first having propagated in the light transmissive panel.