Patent ID: 9684413
Date: 2017-06-20
CPC Classifications: G06F,H04M

Claim:
1. A touch screen, comprising: an activatable display unit comprising a touch surface; a number of light pulse emitting units, connected to said display unit, emitting light pulses over and across said touch surface; a number of light pulse receiving units, connected to said display unit, measuring amounts of light received from said light pulse emitting units; circuitry, connected to said light pulse emitting units and to said light pulse receiving units, selectively activating said light pulse emitting units and said light pulse receiving units; and a calculating unit controlling said display, and controlling said circuitry to operate in an active mode and in an idle mode, wherein (i) in the active mode said display is activated, and said circuitry activates all of said light pulse emitting and receiving units, at a high frequency, and a touch is detected when two or more light pulses emitted by the emitting units are blocked, as determined based on measured amounts of light received at the light pulse receiving units, (ii) in the idle mode said display is not activated, and the calculating unit monitors only a proper sub-area of said display by controlling said circuitry to activate only some of said light pulse emitting units and only some of said light pulse receiving units, at a low frequency, and (iii) the calculating unit switches the circuitry from the idle mode to the active mode in response to determining the presence of an object within the monitored sub-area, based on measured amounts of light received at an activated light pulse receiving unit in the idle mode.